Yonamine, a Nisei Japanese American, was born in Hawaii. A two-sport star, he played running back on the San Francisco 49ers in their second season (1947), becoming the first football player of Japanese ancestry to play in the NFL. In baseball, he was the first American to play professional baseball in Japan after World War II. A multi-skilled outfielder, Yonamine was also noted for his flexible batting style and aggressive bases running during his career with the Yomiuri Giants and Chunichi Dragons.
In the Japanese League, Yonamine was a member of four Japan Series Championship teams, the Central League MVP in 1957, a consecutive seven-time Best Nine Award winner (1952-58), an eleven-time All-Star, a three-time batting champion, and the first foreigner to be a manager (Dragons, 1972-77).
Wally Kaname Yonamine was inducted into the Japanese Baseball Hall of Fame in 1994 for his achievements during his 12-year career with the Giants and Dragons. He is the only American yet admitted into the Hall as a player.
Wally Yonamaine now operates a highly successful pearl store - Wally Yonamaine Pearls - in Roppongi - Tokyo, Japan, with his wife Jane. They also have a branch of their store in California run by their children.