Chinese by ancestry and Hawaiian by birth, Loo spent his youth in Hawaii, then moved to California as a teenager. He graduated from the University of California at Berkeley and began a career in Business. However, the stock market crash of 1929 and the subsequent economic depression forced him to start over. He became involved with amateur, then professional, theater companies and in 1931 made his first film. Like most Asian actors in non-Asian countries, he played primarily small, stereotypical roles, though he rose quickly to familiarity, if not fame, in a number of films.