Peter Cullen almost voiced Optimus Prime like a shouting Hollywood tough guy. His brother Larry was a Marine Corps captain who served in Vietnam. Cullen has said that before his 1984 audition, Larry told him real heroes don't yell: "Be strong enough to be gentle." That advice became Optimus Prime's voice for more than 40 years.

The Real Marine Behind Optimus Prime's Voice

64 viewsPosted 21 days agoUpdated 28 minutes ago

Peter Cullen has voiced Optimus Prime since the character first spoke on screen in 1984, and by his own account, he did not build that voice alone. It came from one piece of advice his older brother gave him right before the audition.

The Advice Before the Audition

Cullen needed his family's only car to get to the tryout. He mentioned to his brother Larry that the role was for a truck who talked like a hero.

Larry did not tell him how to sound tough. He told him the opposite.

"If you are going to be a leader, be a real leader, not a Hollywood leader with the yelling and screaming," Larry told him, according to Cullen. "Be strong enough to be gentle."

A Real Marine, Not a Movie One

Larry Cullen was not repeating a line from a film. He had lived it.

He trained as an officer at Quantico and served as an infantry officer with K Company, 3rd Battalion, 5th Marine Regiment, in Vietnam.

During Operation Hastings in 1966, Larry faced what Peter has described as roughly a one-in-four chance of survival. He came home with a Bronze Star with Combat "V," two Purple Hearts, and the Combat Action Ribbon, and later made captain, serving at Camp Pendleton.

Peter Cullen, older man with grey hair and beard, speaking into a microphone on stage at a Transformers fan convention panel
Peter Cullen has told the story of his brother Larry at Transformers fan conventions for years.

The Voice That Came From a Brother

Cullen has said that when Larry came home from Vietnam, he was different. Quieter. Calmer.

"He was a man and a superhero to me," Cullen has said.

When the Optimus Prime audition came, Cullen did not invent a cartoon voice from scratch. He drew on what he had watched in his own brother.

"My character in The Transformers for Optimus Prime came from Larry," Cullen has said.

Still the Voice, Decades Later

Cullen kept that same voice through the original 1984 cartoon, the 1986 animated movie, and every live-action Transformers film from 2007's Transformers through 2023's Rise of the Beasts.

More than 40 years after a conversation about borrowing the family car, Optimus Prime still sounds like Cullen's brother telling him to be strong enough to be gentle.

A Second Famous Voice

Cullen is also the longtime voice of Eeyore in various Winnie the Pooh productions, a much gentler role he has voiced alongside Optimus Prime since the late 1980s.

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Frequently Asked Questions

Who is the voice of Optimus Prime?
Peter Cullen has voiced Optimus Prime since the original Transformers cartoon debuted in 1984, and has returned for nearly every Transformers series and film since, including 2023's Rise of the Beasts.
Why does Optimus Prime sound the way he does?
Cullen has said he based the character's calm, commanding voice on his older brother Larry, a Marine Corps captain, after Larry told him real heroes do not need to yell to be strong.
Was Peter Cullen's brother really a Marine?
Yes. According to Cullen's own retellings, Larry Cullen served as an infantry officer with the 5th Marine Regiment in Vietnam, survived Operation Hastings, and later made captain, earning a Bronze Star and two Purple Hearts.
Does Peter Cullen voice any other famous characters?
Yes. Cullen has also voiced Eeyore in various Winnie the Pooh productions since the late 1980s, alongside his work as Optimus Prime.
How long has Peter Cullen voiced Optimus Prime?
More than 40 years, from the original 1984 animated series through the 2023 live-action film Transformers: Rise of the Beasts.

Verified Fact

Verified Aug 11, 2026 · 3 sources checked

Source: We Are The Mighty
Show verification details

Claims checked

  • Larry Cullen was a Marine Corps captain who served in Vietnam
  • Larry's advice "be strong enough to be gentle" shaped Optimus Prime's voice, per Peter Cullen's account
  • Peter first voiced Optimus Prime in 1984 and continued for over 40 years

Sources: We Are The Mighty, TFwiki, Wikipedia

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