Martinez started performing early in his life, as a member of his father’s mariachi band at age nine. From there he has been immersed in theater and music, acting in a bilingual repertory theater, La Compania, founded by his mother. After graduating from Hollywood High, he studied at the London Academy of Music and Dramatic Arts, performing in London and throughout Europe. In the United States, Martinez acted in theater companies in New York, Arizona, Seattle and Los Angeles. He performed Shakespeare and was a core member of the Educational Theater Company and Will & Company.
His television career began with the traditional route, with bit parts on “Star Trek: The Next Generation” (Fox, 1987) and “The X-Files,” (Fox, 1993) leading to bigger roles on “NYPD Blue,” (ABC, 1993), “Once and Again, (ABC, 1999) the acclaimed PBS series “American Family” (2002-2004) and “Karen Cisco” (ABC, 2003). He’s also lent his voice talents to two animated “Scooby Doo” projects. His feature film work has included small parts in “Sunset Grill” (1993), “Outbreak” (1995), and “My Family” (1995). In 2004 he appeared in the popular horror indie film “Saw” and as a rival boxing trainer/manager in director/star Clint Eastwood’s “Million Dollar Baby.”
Martizez's most prominent role remains on the edgy surprise hit “The Shield.” While police captains often represent grounded authority figures who provide a stern contrast to the leading men or women on a series, Aceveda is as manipulative and secretive as any classical Machiavellian political figure. The part has required Martinez to hold his own against rogue cop Vic Mackey, as played by Emmy-winner Michael Chiklis. And for a controversial plotline where Aceveda is raped and robbed of his dignity, Martinez earned a Golden Eagle Award from Ricardo Montalban’s Nosotros Foundation.