Often appearing in Westerns, Martínez had roles in Jeremiah Johnson, in which he played a Crow chief, and Ulzana's Raid, which was directed by Robert Aldrich and co-starred Burt Lancaster.

[1][2] Martínez was often typecast in roles that stereotyped Latinos, Native Americans, and Mexicans, but he frequently changed and reworked his characters through his acting, sometimes causing tensions with a production's director.

[1] He moved to Los Angeles, California, shortly after making Pedro Páramo, where he worked as a professional film, television and stage actor for more than thirty years.

[2] In addition to Jeremiah Johnson and Ulzana's Raid, both released in 1972, Martínez was cast opposite Anthony Quinn and Kevin Costner in the 1990 movie, Revenge, as well as the 1993 film, The House of the Spirits.

[1][2] On stage, Martínez was an original cast member for Zoot Suit, which broke sales records for live theater when it opened in Los Angeles in July 1978.