 Walsh's first career was in baseball.After attending Los Angeles High School, where he was an All-City third baseman in 1943, and military service during World War II, Walsh joined the Brooklyn Dodgers organization in 1948 as a member of the front office staff of the Fort Worth Cats, Brooklyn's farm club in the Double-A Texas League.He became the parent team's assistant minor league director, working under Fresco Thompson, in 1951.