Peter Steinfeld is an American personal trainer, fitness entrepreneur and occasional actor best known today as the father of actress and singer Hailee Steinfeld. While Hailee became an Oscar-nominated star, Peter built his own long career in fitness, eventually training celebrity clients including Madonna, Ozzy Osbourne, Glenn Frey and Larry David. He also helped Hailee physically prepare for demanding roles such as Kate Bishop in Marvel’s Hawkeye.
By 2026, Peter’s family life had entered a new chapter too. Hailee married Buffalo Bills quarterback Josh Allen in May 2025 and welcomed their first daughter in April 2026, making Peter a grandfather. Hailee’s family later joked that Peter was officially “clocked in” under his new grandfather name, Pop Pop.
Quick Bio of Peter Steinfeld
| Detail | Information |
|---|---|
| Full Name | Peter Steinfeld |
| Also Known As | Pete Steinfeld |
| Nationality | American |
| Profession | Personal trainer, fitness entrepreneur, occasional actor |
| Known For | Father of Hailee Steinfeld |
| Wife | Cheri Domasin Steinfeld |
| Married | May 24, 1992 |
| Children | Griffin Steinfeld and Hailee Steinfeld |
| Son-in-Law | Josh Allen |
| Granddaughter | Harper Haize Allen |
| Fitness Company | Better Shape-Up |
| Education | Studied business and nutrition at California State University, Northridge |
| Famous Clients | Madonna, Ozzy Osbourne, Glenn Frey, Larry David |
| Acting Credits | Married… with Children, Happy Days, Sisters, Curb Your Enthusiasm |
| Brother | Jake Steinfeld |
| Current Role in Hailee’s Life | Father, supporter and personal trainer |
| Net Worth | Not publicly verified |
There is one important clarification before going further. This Peter Steinfeld is not the Hollywood screenwriter Peter L. Steinfeld who wrote films such as 21, Be Cool and Analyze That. The Peter discussed here is Hailee Steinfeld’s father and a longtime personal trainer.
Who Is Peter Steinfeld?
Peter Steinfeld is a fitness professional who has spent decades helping clients improve strength, conditioning and overall health.
Many readers first learn his name through Hailee.
But he had already established himself in fitness long before his daughter became famous.
People reports that Peter moved to California in 1978, studied business and nutrition at California State University, Northridge, and later founded his own fitness company called Better Shape-Up.
That career eventually brought him into contact with some very famous clients.
Peter Steinfeld Built a Career as a Personal Trainer
Fitness is not simply a hobby for Peter.
It became his profession.
His work has involved helping clients build sustainable exercise habits, improve physical conditioning and change their lifestyles.
People identifies him as an accomplished personal trainer with a long list of celebrity clients.
That career also made him especially useful when Hailee began taking on physically demanding movie and television roles.
She did not need to search far for a trainer.
Her father was already one.
Better Shape-Up
Peter founded a fitness company called Better Shape-Up.
The business reflected his focus on personal training and lifestyle transformation.
According to material cited by People, his work was not simply about making someone look thinner.
The idea was to help clients develop habits they could maintain over time.
That long-term approach is probably one reason he has remained active in fitness for so many years.
Quick fixes come and go.
Healthy routines last longer.
Peter Studied Business and Nutrition
People reports that after moving to California, Peter studied business and nutrition at California State University, Northridge.
Those two subjects fit his later career surprisingly well.
Nutrition relates directly to fitness.
Business helped him build and operate his own training company.
A good trainer needs more than exercise knowledge.
He also needs to understand clients.
Schedules.
Goals.
Motivation.
And how to run a sustainable business.
Peter combined those areas.
Who Has Peter Steinfeld Trained?
Peter’s client list is one of the most interesting parts of his career.
His training business has reportedly worked with stars including:
Madonna.
Ozzy Osbourne.
Glenn Frey.
Larry David.
People specifically highlights these names while discussing his career.
That is a very unusual group.
Music stars.
Comedy stars.
Rock legends.
Each person would have had very different fitness goals.
That kind of variety suggests Peter learned how to adapt his methods to individual clients.
Peter Steinfeld and Madonna
Madonna is famous for maintaining an intense fitness routine throughout her career.
Peter is listed among the celebrity clients he has trained.
Reliable public sources do not provide a detailed timeline of their sessions.
So it would be wrong to invent one.
But her name on his client list gives a sense of the level of people who trusted him professionally.
Training high-profile entertainers can be demanding because their schedules often include touring, filming and constant travel.
Peter Steinfeld and Ozzy Osbourne
Peter also reportedly trained Ozzy Osbourne.
Again, exact details of their workouts are not widely public.
But the connection is interesting.
Ozzy’s life and health history were very different from Madonna’s.
A trainer working with different ages and physical conditions must constantly adjust.
That flexibility is one of the hardest parts of personal training.
One program does not work for everyone.
Larry David Became Part of the Family Story
Larry David is another notable name linked to Peter’s fitness career.
The relationship appears to have lasted beyond ordinary trainer-client contact.
Larry David later attended Hailee Steinfeld and Josh Allen’s May 2025 wedding in California.
That small detail shows how Peter’s fitness career overlapped with his family’s entertainment world.
Professional relationships can sometimes become long friendships.
Peter Steinfeld Married Cheri Domasin in 1992
Peter married Cheri Domasin on May 24, 1992.
Their marriage has lasted more than three decades.
Cheri has her own interesting career story.
She worked as a cosmetologist.
Then a flight attendant.
Later she became an interior designer.
And when Hailee’s acting career began, Cheri became her manager.
That created an unusual family structure.
Mom managed the career.
Dad handled fitness.
And both parents supported their daughter behind the scenes.
How Peter and Cheri Met
Cheri has said that she met Peter while working as a flight attendant.
People notes that meeting him eventually changed the direction of her life.
After getting married and decorating their home, Cheri became interested in interior design.
That later developed into a professional path.
Their story shows how one relationship can influence several parts of a person’s life.
Marriage.
Career.
Family.
And eventually their children’s careers too.
Peter Steinfeld’s Children
Peter and Cheri have two children.
Their son Griffin Steinfeld was born in January 1994.
Their daughter Hailee Steinfeld followed on December 11, 1996.
The two children took very different paths.
Hailee became an actress and singer.
Griffin worked as a race car driver and later became involved in business.
Despite those different careers, Hailee has repeatedly described the family as extremely close.
Peter Steinfeld Is Hailee Steinfeld’s Father
Hailee has often spoken warmly about Peter.
She has said that she would not be where she is without her parents and brother.
In a 2023 interview, she credited them with keeping her grounded and making major sacrifices for her career.
That support began early.
Hailee became interested in acting as a child.
Her mother required her to study acting seriously before pursuing auditions.
Peter supported the process too.
As her career became more physical, his own profession became especially valuable.
Peter Helped Hailee Train for Movie Roles
Peter has trained Hailee for years.
That includes helping her prepare for tours and acting roles.
Hailee once explained that there is a difference between “Dad” and “Pete.”
Most of the time he is supportive.
But once she gives him a specific physical goal and deadline, he becomes her trainer and stops accepting excuses.
That is probably a strange dynamic.
Imagine your father being both the person cheering for you and the person making you finish one more set.
For Hailee, that became normal.
Peter Trained Hailee for Hawkeye
One of their biggest professional collaborations came before Marvel’s Hawkeye.
Hailee played Kate Bishop.
The role required archery.
Hand-to-hand combat.
Stunts.
Movement training.
And physical endurance.
Hailee said that before filming in Atlanta, she spent months training in Los Angeles with Peter.
They worked on different fighting styles and exercises aimed at preparing the muscles needed for archery.
That made Peter part of the preparation behind one of Hailee’s biggest roles.
Training Kate Bishop Was Different
Playing Kate Bishop required more than looking athletic.
The character actually had to move like an athlete.
That means strength.
Coordination.
Reaction speed.
Conditioning.
Hailee also had to make the physical scenes look believable on camera.
Peter helped prepare her body before professional stunt teams took over on set.
It is a good example of how his career directly supported hers.
Peter Has Trained Hailee Since She Was Young
Hailee has also spoken about doing kickboxing with her father for years.
Women’s Health reported that fitness became a regular part of her relationship with Peter.
That long history probably made their later professional training easier.
Peter already understood how Hailee moved.
What motivated her.
Where she struggled.
And when she needed pushing.
That kind of personal knowledge can be difficult for an outside trainer to match.
Peter Appeared in Hailee’s “Most Girls” Video
Peter even made a brief appearance in Hailee’s 2017 music video for “Most Girls.”
People notes that he can be seen coaching Hailee while she boxes.
It was a perfect cameo.
He did not need to pretend to be something different.
He simply played the role he already had in real life.
Trainer.
Coach.
Dad.
Peter Steinfeld Has Also Acted
Fitness is Peter’s main career.
But he has also appeared on television.
People reports that he appeared in three episodes of Married… with Children.
His other credits include appearances on:
Happy Days
Sisters
Curb Your Enthusiasm
These were small roles rather than a full-time acting career.
Still, it gives Peter another connection with the entertainment industry.
Peter Steinfeld and Jake Steinfeld
Peter is the brother of Jake Steinfeld, another well-known fitness personality.
Jake became famous through fitness programs, acting appearances and the Body by Jake brand.
He also founded Major League Lacrosse and has been involved in multiple sports and fitness ventures.
Hailee therefore grew up in a family where fitness was already important before she became famous.
Her father was a trainer.
Her uncle became a nationally known fitness personality.
That environment likely helped shape her own attitude toward exercise.
Peter’s Jewish Background
Hailee’s public biography identifies Peter as Jewish.
Cheri is Christian.
Hailee has said that she grew up celebrating both sides of the family’s traditions.
That mixed religious background became part of Hailee’s upbringing.
It also shows something about Peter and Cheri’s household.
Different backgrounds did not stop them from building a family together.
They allowed their children to experience both traditions.
Peter and Hailee at the Oscars
One of the most memorable family appearances happened at the 2011 Academy Awards.
Hailee had been nominated for Best Supporting Actress for True Grit.
She was only 14.
Peter, Cheri and Griffin joined her for the event.
Imagine that moment from a parent’s perspective.
Your teenage daughter has gone from auditions to one of the biggest awards shows in the world.
Peter looked every bit the proud father.
His Support Continued as Hailee Grew Up
Hailee’s career did not stop with True Grit.
She moved into:
Pitch Perfect.
The Edge of Seventeen.
Music.
Bumblebee.
Dickinson.
Marvel.
Sinners.
Through all of that, Peter remained part of her support system.
He has attended premieres.
Awards events.
Family celebrations.
And continued training her physically.
That is a rare combination of personal and professional support.
Peter Became Josh Allen’s Father-in-Law
Hailee began dating Buffalo Bills quarterback Josh Allen in 2023.
The couple became engaged in November 2024.
They married on May 31, 2025, in California.
That made Peter the father-in-law of one of the NFL’s biggest stars.
The wedding brought together two very different worlds.
Hollywood.
And professional football.
But Peter probably had more in common with an elite athlete than many celebrity parents would.
Fitness had been his career for decades.
Peter Steinfeld Became a Grandfather in 2026
An even bigger family milestone arrived the following year.
Hailee and Josh welcomed a baby daughter in April 2026.
That made Peter a grandfather for the first time.
People reported that Hailee’s family celebrated their new family roles and referred to Peter as “Pop Pop.”
That is one of the sweetest updates in his 2026 story.
For decades he had been Hailee’s trainer and father.
Now he had another title.
Grandfather.
Peter Is Still Training Hailee in 2026
Becoming a grandfather did not end the trainer-daughter partnership.
In June 2026, Hailee said she had begun increasing her workout routine after pregnancy and was back training with her father.
She jokingly described him as her “trainer aka Dad.”
That means their working relationship has now lasted through several stages of her life.
Teen actress.
Pop singer.
Marvel star.
Wife.
Mother.
Peter has remained part of the routine.
Post-Pregnancy Fitness
Hailee’s 2026 return to exercise was naturally different from previous movie training.
She had recently had a baby.
That means the body needs recovery and a gradual approach.
E! reported that she was beginning to ramp up her routine with Peter’s help.
The important point is not how quickly someone “gets back in shape.”
It is that Hailee chose a trainer she trusted.
And that trainer happened to be her father.
Peter’s Relationship With Hailee Today
Their relationship appears extremely close.
Peter has publicly celebrated his daughter’s achievements.
Hailee has repeatedly credited him with supporting her.
In one birthday message, he wrote about how proud he was not simply of her fame but of the woman she had become.
That difference matters.
Parents can be impressed by awards.
But his message focused on character.
That probably explains why Hailee speaks about her family with such loyalty.
How Old Is Peter Steinfeld?
Peter’s exact birth date and age are not consistently established through major reliable sources.
Some biography websites publish dates.
But they often mix him with other people named Peter Steinfeld.
That creates a real risk of error.
Because of that, it is better not to publish a precise age unless Peter or a strong primary source confirms it.
We do know that he moved to California in 1978 and has spent decades working as a trainer.
Peter Steinfeld’s Net Worth
There is no reliable public figure for Peter’s personal net worth.
He has had a long career.
He has trained famous clients.
He founded his own company.
His daughter is highly successful.
None of that tells us exactly how much money he personally owns.
Celebrity net-worth websites often create numbers without showing how they calculated them.
Those estimates should not be treated as fact.
Is Peter Steinfeld a Screenwriter?
No—not the Peter Steinfeld discussed in this article.
A separate man named Peter L. Steinfeld is a screenwriter known for Drowning Mona, Analyze That, Be Cool and 21.
That screenwriter is married to DeShawn Schneider and has a different family history.
Hailee Steinfeld’s father is a personal trainer and occasional actor.
The shared name causes a lot of confusion online.
Keeping the two men separate is essential.
What Is Peter Steinfeld Doing in 2026?
Peter remains active in fitness and in Hailee’s life.
Most notably, Hailee revealed in June 2026 that she was again working out with him as she resumed regular training after having her daughter.
He is also enjoying a new family role as grandfather to Harper Haize Allen.
So his 2026 life seems to bring together the two things most closely associated with him.
Fitness.
And family.
Final Thoughts
Peter Steinfeld has spent decades building a life around fitness and family.
He moved to California in 1978, studied business and nutrition, created Better Shape-Up and trained high-profile clients including Madonna, Ozzy Osbourne, Glenn Frey and Larry David.
He also married Cheri Domasin in 1992 and became the father of Griffin and Hailee Steinfeld.
When Hailee’s career took off, Peter became more than a proud dad.
He became part of her professional support system.
He helped her train for tours.
Taught her through years of fitness work.
Prepared her for the physical demands of Hawkeye.
And even appeared as her boxing coach in the “Most Girls” music video.
By 2026, his family had grown again.
Hailee was married to Josh Allen.
She had welcomed daughter Harper Haize.
And Peter had become “Pop Pop.”
Yet even with that new role, he was still doing what he had done for years.
Training his daughter.
Supporting his family.
And staying mostly outside the celebrity spotlight.
That may be the easiest way to understand Peter Steinfeld.
Hailee became the star.
Peter remained one of the people helping her stay strong enough to shine.
FAQs About Peter Steinfeld
Who is Peter Steinfeld?
Peter Steinfeld is an American personal trainer and occasional actor best known as Hailee Steinfeld’s father. He founded Better Shape-Up and has trained several celebrity clients.
What does Peter Steinfeld do for a living?
He is a personal trainer and fitness entrepreneur.
Who is Peter Steinfeld married to?
He is married to Cheri Domasin Steinfeld. They married on May 24, 1992.
How many children does Peter Steinfeld have?
Peter and Cheri have two children, Griffin Steinfeld and Hailee Steinfeld.
Is Peter Steinfeld Hailee Steinfeld’s trainer?
Yes. Peter has trained Hailee for years and helped her prepare for physically demanding projects including Hawkeye.
Who has Peter Steinfeld trained?
People reports that his clients have included Madonna, Glenn Frey, Ozzy Osbourne and Larry David.
Did Peter Steinfeld act on television?
Yes. His credits include appearances on Married… with Children, Happy Days, Sisters and Curb Your Enthusiasm.
Is Peter Steinfeld related to Jake Steinfeld?
Yes. Jake Steinfeld is Peter’s brother and Hailee’s uncle.
Is Peter Steinfeld Josh Allen’s father-in-law?
Yes. Hailee Steinfeld married Buffalo Bills quarterback Josh Allen on May 31, 2025.
Is Peter Steinfeld a grandfather?
Yes. Hailee and Josh welcomed daughter Harper Haize Allen in April 2026, making Peter a grandfather. The family refers to him as “Pop Pop.”
Is Peter Steinfeld the screenwriter who wrote 21 and Be Cool?
No. That is a different Peter Steinfeld. Hailee’s father is a personal trainer.
What is Peter Steinfeld’s net worth?
No reliable public source has confirmed his exact net worth.
What is Peter Steinfeld doing in 2026?
He remains involved in fitness and continues training Hailee. She said in June 2026 that she had returned to workouts with her father after welcoming her daughter.
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