Mako was born Makoto Iwamatsu in Kobe, Japan, on December 10, 1933. He moved to the United Stage when he was 15. Mako enrolled in school, but eventually was drafted and spent two years in the military. When he got out, he went to California to study theater at the Pasadena Playhouse. In California he worked in regional theater and appeared in small roles in a variety of television series before landing his big break in the mid-1960s. It was then he was cast as Po-han in the film The Sand Pebbles, which earned him an Academy Award nomination. Around that same time, Mako co-founded with Beulah Quo East West Players, the nation's first Asian American theater company. Mako served as the group's first artistic director. Although he continued to work on both the small and big screens, Mako dedicated much of his time to his theater group and insuring that Asian-Americans would have a chance to act in a wide variety of roles. On Broadway, Mako starred in the original mounting of Pacific Overtures, receiving a Tony nomination for his performance. He also appeared on the Great White Way in Shimada.