Leemans appeared in 80 NFL games with the Giants from 1936 to 1943. He totaled 3,132 rushing yards on 919 carries (3.4 yards per carry) and 17 rushing touchdowns, 2,318 passing yards and 25 passing touchdowns, 422 receiving yards on 28 receptions, and 339 yards on punt and kickoff returns. Leemans also played on defense. Alex Wojciechowicz, a fellow Pro Football Hall of Fame inductee who played against Leemans, recalled: "Leemans was probably greater on defense than he was on offense. He was a bugger on defense, all over the field, always in on the action."