In 1920, Kunz began his professional career with the Sacramento Senators. That season, he went 3–11 with a 4.78 earned run average (ERA) in 39 games. His second season, Kunz went 14–12 with a 3.79 ERA in 50 games. He led all Senators pitchers in games played (50), and was second in bases on balls (walks) allowed (103).[2]