Peter Cullen is a Canadian voice actor born in Montreal, Quebec, on July 28, 1941. He was a member of the first graduating class of the National Theatre School of Canada in 1963, which provided a foundation for his extensive career in performance. His professional journey began in the 1960s with work in radio and television, including roles on comedy programs and as an announcer for series such as The Smothers Brothers Comedy Hour. This early experience allowed him to hone his vocal skills and establish a presence in the entertainment industry.

In the realm of anime and animated series adapted from Japanese properties, Cullen became a prominent voice during the 1980s. He is notably recognized for his multiple roles within the Voltron franchise. In the series Voltron: Defender of the Universe, he voiced several characters, including Coran, the royal advisor to Princess Allura, and King Alfor, the deceased father of Princess Allura whose ghost appears to provide guidance. For the Vehicle Voltron series, he took on the role of Commander James Hawkins, the officer in charge of the Galaxy Alliance starship Explorer who commands the Vehicle Voltron team. His involvement with the franchise extended to the 1986 television special Voltron: Fleet of Doom, where he reprised his roles as Commander James Hawkins and King Alfor, in addition to voicing the character Hutch, Viceroy Throk, and serving as the narrator. Other notable anime voice work from this period includes voicing multiple characters in Saber Rider and the Star Sheriffs, such as the transforming robot Ramrod, Commander Eagle, and the villainous Nemesis, as well as providing the narration for the series Macron I.

Beyond his contributions to anime, Cullen is internationally renowned for his portrayal of Optimus Prime, the leader of the Autobots, which began with the original 1980s Transformers animated series. He based the character's calm and authoritative voice on his brother, a United States Marine Corps veteran. He returned to this signature role for the live-action Transformers film series starting in 2007 and for subsequent animated series like Transformers: Prime, for which he received a Daytime Emmy Award nomination. His extensive voice portfolio also includes a long tenure as Eeyore in the Winnie the Pooh franchise, Monterey Jack in Chip 'n Dale: Rescue Rangers, the villainous Venger in Dungeons & Dragons, and the first voice of the K.A.R.R. unit in the live-action series Knight Rider. For his enduring impact and contributions, Cullen has been honored with induction into the Transformers Hall of Fame and received a Lifetime Achievement Award from the National Academy of Television Arts and Sciences.