Peter Cullen died on Wednesday, August 26, at his home in Los Angeles. He was 85. His agent confirmed the death and no cause has been disclosed.

His family asked that people “honor his remarkable legacy by serving your communities and leading others with compassion, integrity, and loyalty, and always remember, ‘be strong enough to be gentle.’”

That last phrase is not a line from the obituary desk. It is where Optimus Prime came from, and Cullen had been telling people so for forty years.

The advice that made the voice

Cullen was born Peter Claver Cullen in Montreal on July 28, 1941, to American parents, and he was in the first graduating class of the National Theatre School of Canada in 1963. He spent his early career as a radio announcer on CKGM in Montreal, then as the announcer on The Smothers Brothers Comedy Hour, then as a series regular on The Sonny and Cher Comedy Hour. By 1984 he had two decades of comedy and announcing behind him and no particular reason to expect that a toy commercial franchise would define him.

He read the character breakdown for Optimus Prime at a casting house in Burbank and, by his own account, thought it was the opportunity of the year. What he did next is the part every fan can recite. He went to his older brother Larry, a retired captain in the United States Marine Corps who had served in Vietnam, and Larry told him this:

“Peter, don’t be a Hollywood hero, be a real hero. Real heroes don’t yell and act tough; they’re tough enough to be gentle, so control yourself.”

So Cullen did not play a general. He played a man who had already seen what he was protecting people from. “When he came home, I could see a change,” he said of his brother. “He was quieter and he was a man and a superhero to me. I watched him and listened to him. I’d never had an opportunity to do a superhero, and when that came, that voice just came right out of me and I sounded like Optimus.”

He got the part. Then his agent, Steve Tisherman, called back to say he had also landed Ironhide, which Cullen called a home run. Across the original 1984 to 1987 run he is credited with Optimus Prime, Ironhide, Streetwise, Wingspan, Slugslinger and Nightstick, which is to say he was the Autobot leader and also several of the people the Autobot leader was talking to.

Optimus Prime mid-transformation, his blue helmet and silver faceplate risen above the red cab of his truck mode, orange marker lights along the roof, grey machinery behind him.

Optimus Prime arriving at the Battle of Autobot City, The Transformers: The Movie, 1986. Ten minutes of screen time later the film does the thing nobody had warned the audience about.

1986, and the thing nobody at the studio saw coming

Cullen said afterwards that he had no idea how popular the character was until they killed him. The studio had never passed on the fan mail addressed to Optimus Prime, so he had been recording the role for two years without knowing that children were writing to it.

Then The Transformers: The Movie put Prime on a slab in the medical bay, had him hand the Matrix of Leadership to the next Autobot in line, and drained the colour out of him while the audience watched.

A red robotic arm and dark blue hand holding the Matrix of Leadership, its silver casing split open around a glowing blue core, with a second blue hand reaching in from the left.

The Matrix of Leadership changes hands. Whatever else the 1986 film got wrong, it staged this properly.

Optimus Prime drained of all colour to a flat grey, head tilted back and body slumped against a pale pink wall in the Autobot medical bay.

The colour goes out of him. Children left cinemas in 1986 in genuine distress, and the production was not remotely prepared for it.

The backlash surprised the producers badly. Children came out of theatres upset in a way that a toy tie-in film had not planned for. Prime was brought back for a single season three episode, “Dark Awakening”, which was meant to be the end of it. The requests kept coming. So they made “The Return of Optimus Prime” as a two parter, altered the original ending of “Dark Awakening” in reruns to tease it, and Prime led the Autobots through the final five episodes of the original American series.

It is worth being precise about what that means. The most famous fan campaign in the franchise’s history was not about a toy or a continuity decision. It was about wanting to hear one specific man’s voice again.

Twenty one years, and then he was back

The role went to other actors for a long stretch. Neil Kaplan had it in Robots in Disguise from 2001, Garry Chalk through the Unicron Trilogy from 2002 to 2006. Cullen came back in 2007 for the first live action film and then simply did not leave.

He voiced Optimus Prime in Revenge of the Fallen, Dark of the Moon, Age of Extinction and The Last Knight, then in Bumblebee and Rise of the Beasts. He was only contractually committed as far as The Last Knight. In 2021 producer Lorenzo di Bonaventura said Cullen was welcome to keep the part for as long as he wanted it, which is an unusual thing for a studio to say out loud about a voice role and a fair measure of how untransferable everyone understood it to be.

On television he carried Transformers: Prime from 2010 to 2013, and was nominated for a Daytime Emmy for Outstanding Performer in an Animated Program for its first season. He did five years of Rescue Bots, then Robots in Disguise, Titans Return and Power of the Primes. He recorded the role for War for Cybertron, Fall of Cybertron, Devastation, Earth Wars and, in 2023, Fortnite. He is the voice on Transformers: The Ride 3D. If you have heard Optimus Prime speak at any point since 2007, in almost every case you have heard Peter Cullen.

What the industry did about it while he was alive

This is the part that reads better today than most of these sections do, because the honours did not wait.

At BotCon 2010 Hasbro named him one of the first four human inductees into the Transformers Hall of Fame. On September 30, 2014, outside the TCL Chinese Theatre in Hollywood, he knelt down and pressed his hands into wet cement in the courtyard, at a ceremony held for Optimus Prime, who was given a tyre print in a second slab. The photograph at the top of this page is from that afternoon.

In 2023 the National Academy of Television Arts and Sciences gave him a Lifetime Achievement Award at the second Children’s and Family Emmy Awards.

Peter Cullen at a convention table in 2024, smiling, holding up an open replica Matrix of Leadership with both hands.

Cullen with a replica Matrix at a Portland convention in 2024. He signed at these for decades and was, by every account anyone has ever published, unfailingly decent about it.

The rest of the career, which was not small

Reducing him to one robot does him a disservice, so, briefly: he was Eeyore in the Winnie the Pooh franchise from 1988 to 2023, which is the only other role he held for anything like as long. He was Monterey Jack in Chip ‘n Dale: Rescue Rangers, Venger in Dungeons and Dragons, Coran and King Alfor in Voltron, the first voice of KARR in Knight Rider, and Mario in the Donkey Kong segments of Saturday Supercade in 1983, making him the first person to voice Mario in western media.

He also supplied the vocalisations for the title creature in Predator in 1987. The gentlest voice in children’s television and the clicking in the trees were the same man in the same year.

Most recently he was Thaedus in Invincible, from 2023 through this year. His friend Frank Welker, who has been Megatron opposite him since 1984, joined the fourth season as Emperor Argall, a character positioned against Thaedus. The two of them had been reprising that rivalry, on purpose, forty years on.

Peter Cullen standing at a microphone on a darkened stage at the Kennedy Space Center in 2011, wearing a white polo shirt.

Cullen speaking at the Kennedy Space Center in 2011. He traced his interest in spaceflight to watching Apollo 11 in 1969, and named the scene between Optimus Prime and Buzz Aldrin in Dark of the Moon as one of his proudest moments.

Where to go next on this site

Our guide to the voice cast of the 1984 series is where the rest of that room is documented. The Optimus Prime encyclopedia entry collects the character across every continuity, and our page on The Transformers: The Movie covers the 1986 film in full, including the sequence above.

We are not going to tell you which episode to put on tonight. You already know.

Sources