A star righthanded pitcher, Mallon played three seasons with McKinley High School, where he led the league in strikeouts. He also played with the Anheuser-Busch American Legion team.

Robert signed with the New York Yankees out of high school and roomed with Hall of Famer Mickey Mantle in the lower minor leagues. Mallon finished his pro career in 1952, returning to help Jokers A.C. win the Khoury League Senior championship in 1955. After that, Mallon began a long association with the Red Villas.

Robert E. Mallon passed away on January 8, 2023.