Gary Chalk is a British-born Canadian actor widely recognized for his extensive voice work in animated series, particularly within the Transformers franchise. Born in Southampton, England in 1952, he moved with his family to Vancouver, Canada at the age of five. He began his career in professional theatre in 1978, performing with numerous companies in British Columbia, including the Vancouver Playhouse Theatre Company and the Arts Club Theatre Company, before transitioning to a prolific career in film and television.

Chalk is perhaps best known for his iconic portrayals of heroic Autobot leaders in the Transformers universe. He first voiced the character Optimus Primal in the series Beast Wars: Transformers and its sequel Beast Machines. He later took on the role of Optimus Prime in the anime English dubs that formed the Unicron Trilogy, which includes Transformers: Armada, Transformers: Energon, and Transformers: Cybertron. His association with the franchise is so significant that he has voiced an Optimus character in more episodes than any other actor.

Beyond Transformers, Chalk's voice acting career is remarkably extensive, spanning thousands of animated productions. His notable roles include Grounder in Adventures of Sonic the Hedgehog and Dr. Ivo Robotnik in Sonic Underground. He has also been a recurring presence in various other animated series, voicing characters such as King Hippo in Captain N: The Game Master, Guts Man in the 1990s Mega Man cartoon, and later Dr. Light in Mega Man: Fully Charged. His filmography includes voice work for He-Man and the Masters of the Universe, G.I. Joe, My Little Pony: Friendship Is Magic, and many others.

In addition to his voice work, Chalk has enjoyed a successful on-screen acting career, often portraying law enforcement figures. He is known for his recurring role as Inspector Andrew Pawlachuk on the Canadian drama Cold Squad, a performance that earned him Gemini Awards for Best Supporting Actor in a Drama Series for two consecutive years. His other on-screen credits include appearances in Stargate SG-1, The Killing, Eureka, and films such as Freddy vs. Jason and Godzilla. In early 2026, it was reported that Chalk was in full remission from cancer and was returning to work.