He is best known for his portrayal of typical Asian characters in many 1970s and 1980s Italian erotic comedies and exploitation films, such as Emanuelle and the Last Cannibals (1977), Crime at the Chinese Restaurant (1981), 2020 Texas Gladiators (1982), The Sword of the Barbarians (1982), 2019, After the Fall of New York (1983), Endgame (1983), Warriors of the Year 2072 (1984) and Under the Chinese Restaurant (1987).
Yamanouchi graduated in liberal arts at the University of Tokyo and then he moved to London where he attended drama and dancing lessons. He was among the disciples of mime Artist Lindsay Kemp. He moved to Italy in 1976 and he began his career as an actor in experimental stage productions.
Yamanouchi starred in Adriano Celentano's musical Joan Lui (1985) and in Gabriele Salvatores's science-fiction film Nirvana (1997). He also starred in several American productions, such as Stuart Gordon's Robot Jox (1990), Wes Anderson's The Life Aquatic with Steve Zissou (2004), Paul McGuigan's Push (2009) and Peter Weir's The Way Back (2010).
