Was diagnosed with acute myeloid leukemia in 1989. Since then he had fallen ill only once in 1994, but is now a fully recovered actor.

Children: son, actor Dai Watanabe (born August 1st 1984) and daughter, An Watanabe (born 1986).

One of eight actors of Asian descent nominated for an Academy Award in an acting category. The others are Miyoshi Umeki who won Best Supporting Actress nominated for Sayonara (1957), Sessue Hayakawa nominated for The Bridge on the River Kwai (1957), Mako nominated for The Sand Pebbles (1966), Ben Kingsley who won Best Actor for Gandhi (1982), Haing S. Ngor who won Best Supporting Actor for The Killing Fields (1984), Pat Morita nominated for The Karate Kid (1984), and Rinko Kikuchi nominated for Babel (2006).

One of six Asian actors nominated for an Academy Award in an acting category. The others are Miyoshi Umeki who won Best Supporting Actress nominated for Sayonara (1957), Sessue Hayakawa nominated for The Bridge on the River Kwai (1957), Mako nominated for The Sand Pebbles (1966), Haing S. Ngor who won Best Supporting Actor for The Killing Fields (1984) and Rinko Kikuchi nominated for Babel (2006).