Alexander Harper Berkeley is an American actor. He is known for his television roles as Sheriff Thomas McAllister on the crime drama The Mentalist, George Mason on the political thriller series 24, Percy Rose on the action thriller series Nikita, the Man on The Booth At The End and Gregory in AMC's The Walking Dead. His notable film roles include Todd Voight in , Agent Gibbs in Air Force One, Bowery Snax in Sid and Nancy, Dr. Lamar in Gattaca, Trevor Lyle in Candyman and Ralph in Heat.
Berkeley began playing roles in 1981, with early appearances in M*A*S*H, Cagney & Lacey, Remington Steele, Miami Vice, Moonlighting, and The A-Team. Although not becoming a household name, Berkeley's face was increasingly recognizable into the 1990s. His later television guest roles included The X-Files, ', ER, and Law & Order. On the big screen, Berkeley has appeared in North Country, ', Mommie Dearest, Phoenix, Kick-Ass, A Few Good Men, The Rookie, Candyman, Apollo 13, Leaving Las Vegas, Gattaca, The Rock, Air Force One, Sid and Nancy, Spawn, Amistad, Shanghai Noon, Barb Wire, and Timecode. Berkeley has the distinction of appearing in both the made-for-television filmL.A. Takedown in 1989 and its 1995 critically acclaimed theatrical remake Heat, both directed by Michael Mann. Several of his earlier roles were in films by director Alex Cox. In 2001, Berkeley became a recurring guest star and later on a series regular on 24 in the role of George Mason, the head of the counter-terrorist unit. He portrayed the mysterious John Smith on the CBS drama Jericho. In 2010, he received one of his best-known roles, that of Percy Rose in the CW action-thriller series Nikita. He portrayed the character as a series regular in the show's first two seasons, as well as being the series' de factomain antagonist of its first two seasons. Berkeley was Sheriff Thomas McAllister on The Mentalist. Berkeley portrayed Gregory on AMC's The Walking Dead, originally in a guest role in season six, but was promoted as a series regular for season seven. In 2018, he portrayed Peter Lockwood, father of Agent Liberty, on season 4 of CW's Supergirl.
Voice work
Berkeley has provided voices for animated series such as Aaahh!!! Real Monsters, Teen Titans, and Gargoyles. He voiced Quentin Beck/Mysterio in The Spectacular Spider-Man, Captain Atom in the animated movie , and Dr. Kirk Langstrom in Son of Batman.
Awards
In 2013, Berkeley won the Streamy Award "Best Male Performance, Drama" for his starring role in the acclaimed webseries, The Booth at the End.