Born in Salina, Kansas, he was raised there and in Los Angeles, where he graduated from John C. Fremont High School. His professional baseball career began in 1943, when he was 17. Reaching the majors the following season during the World War II manpower shortage, Mauch played for six different clubs over all or parts of nine MLB seasons between and . In 304 games and 737 at-bats, Mauch hit .239, with 176 hits, including 25 doubles, seven triples and five home runs. He was credited with 62 RBIs, striking out 82 times. He missed part of 1944 and all of the season while performing wartime service in the United States Army Air Forces.