Shimono, a Japanese American, was born Saburo Shimono in Sacramento, California, the son of restaurant owners Edith Mary (née Otani) and Masauchi Shimono. Shimono is the twin brother of Dr. Jiro Shimono, director of the Delaware Psychiatric Center. Shimono is a graduate of the University of California, Berkeley.
He is an accomplished stage actor as well, having appeared on Broadway and in regional theaters including San Francisco's American Conservatory Theater and Berkeley Repertory Theater. One of his more memorable roles was as Hiroshi Kawamura in the 1990 drama Come See the Paradise. He also had a role in the 2008 independent film, Americanese.
Shimono played a Korean spy on the popular, long-running, TV series, M*A*S*H, in the episode "Dear Comrade"; provided the voice of antique shop owner/Chi Wizard, Uncle Chan, on the hit TV series Jackie Chan Adventures, The Emperor, Jack's father, in the hit TV series Samurai Jack.
He won a CLIO Award in 1984 for Best Actor in a commercial.