The one and only! Peter Cullen is a Canadian voice actor and the original voice of Optimus Prime in the 1980s cartoon series. Optimus Prime is the leader of the Autobots who transforms into a rusty Marmon 97 semi truck and later, a blue and red Western Star 4900 Phantom Custom semi-trailer truck. In Age of Extinction fans are treated to the powerful baritone of “angry Optimus Prime.”.