He began his career in 1928 for the Pittsburgh Pirates, playing 50 games. After spending his first two seasons backing up Charlie Hargreaves, he became the starting catcher for the Pirates for the 1930 season. The following season, Hemsley played 10 games before he was traded to the Chicago Cubs for Earl Grace. He spent his time as a Cub backing up Hall of Famer Gabby Hartnett, though was able to bat .309 during his tenure on the Cubs for the 1931 season. He played with the Cubs during their run to the 1932 World Series, though Hemsley ended up without a hit in three pinch hit appearances. At the end of the 1932 season, Hemsley was traded to the Cincinnati Reds along with Johnny Moore, Lance Richbourg, and Bob Smith for Babe Herman. He struggled in Cincinnati, hitting under .200 while playing under another Hall of Famer, Ernie Lombardi. On August 12, 1933, he was traded to the St. Louis Browns for Jack Crouch.