Kusatsu was born and raised in Honolulu, Hawaii, where he attended Iolani School. He began acting in Honolulu summer stock, and after studying theater at Northwestern University, started to make his mark on the small screen in the mid-1970s. Usually mustachioed, with a dapper, professional air, he has most often played doctors, but his repertoire has included a generous sampling of teachers (usually college professors), businessmen, detectives, church ministers and other intelligent, middle-class types. Kusatsu is married to Gayle Kusatsu; they have two sons, Kevin and Andrew.
Kusatsu has been a regular on several series, but neither the 1982 adventure Bring 'Em Back Alive nor the Hawaiian-set 1989 medical drama Island Son, in which he played one of Richard Chamberlain's colleagues, lasted very long. His many television movies have included the 1976 film adaptation of Farewell to Manzanar, about Japanese American internment during World War II. Other M.O.W.s and mini-series have been And The Sea Will Tell, and American Tragedy playing Judge Lance Ito. He had a memorable role in the 1976 "Baa Baa Black Sheep" episode Prisoners of War as a downed Japanese fighter pilot in the Pacific. Kusatsu also guest-starred on an episode of Lou Grant on Japanese internment in the U.S., Golden Land a 1988 Hollywood-set drama based on a William Faulkner story; and the 1993 AIDS drama And the Band Played On. He appeared in four M*A*S*H episodes and later starred in the short-lived mid-1990s A.B.C. series All American Girl, the first East Asian familiar sitcom in the U.S.