Keith Diamond is an American actor and voice actor born on March 26, 1962, in the Jamaica neighborhood of Queens, New York. He began his on-screen acting career in 1983 with a role in the film All the Right Moves. Over the subsequent decades, he built a extensive list of credits in television, appearing in guest-starring roles on numerous series such as Martin, ER, Charmed, The Shield, Prison Break, Criminal Minds, and Bones. He also had a recurring role as Greg Clemens on The Drew Carey Show. His film appearances include roles in Awakenings, Desperate Measures, and Baby Boy.

In addition to his live-action work, Diamond has contributed his voice to several animated projects. He is perhaps best known in animation for his role as the voice of Agent J in the Men in Black: The Series, which aired from 1997 to 2001. His involvement with the Transformers franchise includes voice work in two related series. He was part of the English-language voice cast for the 2000 anime series Transformers: Car Robots. When that series was adapted and dubbed for an American audience as Transformers: Robots in Disguise in 2001, he reprised his role, voicing the character Rapid Run, a member of the Autobot Team Bullet Train. His other voice acting credits include the direct-to-video animated film Kangaroo Jack: G'Day U.S.A.! in 2004 and the Adult Swim series Stroker and Hoop.