His agent, Kevin Motley, said Cullen died on Wednesday at his home in Los Angeles.
"His family asks that you honour his remarkable legacy by serving your communities and leading others with compassion, integrity, and loyalty and always remember 'be strong enough to be gentle,'" said a family statement.
Cullen's career spanned from being an announcer at the groundbreaking late-1960s comedy and variety series The Smothers Brothers Comedy Hour and joining comedy sketches for Sonny & Cher to voice acting in The Smurfs and multiple G.I. Joe iterations. But he struck a nerve as Optimus Prime.
While the original cartoon ran just a few years, it left an indelible mark on pop culture, with a toy line, spin off cartoon series and comics produced over the next two decades. That culminated in the launch of a multibillion-dollar, live-action film franchise in 2007.
Before his audition, Cullen only knew that he would be reading for the part of a truck, though giving voice to a vehicle didn't seem that crazy.
"You're always auditioning for something in animation that's a little off of the norm," Cullen told the AP in 2019.
When Cullen read about the heroic Autobot leader that turned into a red cabover semitrailer, he thought about his older brother, who had served as a US Marine in the Vietnam War.
"He was my hero, and he certainly was the mainstay behind the character," Cullen said. "I just did an impression of Larry, and he's still alive in my mind today because every time I do Prime, there's my brother Larry."
Cullen's authoritative baritone as Optimus Prime also appeared in 2009's Transformers: Revenge of the Fallen through Dark of the Moon, Age of Extinction, The Last Knight, Bumblebee and Rise of the Beasts in 2023.
His thoughtful, almost operatic lines would be quoted for decades by kids and adults alike: "I am Optimus Prime, and I send this message to any surviving Autobots taking refuge among the stars: We are here. We are waiting," he said in the first movie.
In another, Cullen intoned: "Fate rarely calls upon us at a moment of our choosing."
Other highlights from Cullen's prolific career include voicing Eeyore across various Winnie-the-Pooh projects, including Disney's The New Adventures of Winnie the Pooh TV series that aired from 1988-91, as well as voicing the villainous KARR opposite KITT in the 1980s series Knight Rider, and lending his pipes to King Kong in the Jeff Bridges-led King Kong remake in 1976.
Cullen received a lifetime achievement award at the Children's & Family Emmy Awards in 2023 and was nominated for a Daytime Emmy for voicing Optimus Prime in 2011.
14°C