Shantz played the first chunk of his career with the Philadelphia/Kansas City Athletics, first debuting in 1949. Shantz was an All-Star for the first time in 1951 with an 18-10 record. The southpaw followed that with the best year of his life when he led the American League in Wins (24), WHIP (1.048), and SO/BB (2.41), where Shantz was an All-Star and won the MVP.
Shantz's career plummeted after with injuries and poor play. He was traded to the New York Yankees, where he had a rebound season in 1957, where he led the AL in ERA (2.45) and was an All-Star for the third and final time. Shantz later helped New York win the World Series in 1958, but he was again a bullpen player. Shantz hung on to 1964, playing for Pittsburgh, Houston, St. Louis, Chicago (NL), and the Phillies.
A notable fact on Shantz was that he was an excellent fielding Pitcher. When the Gold Glove was first given out in 1957, Shantz was the first winner (that year was the only year given throughout the Majors and not the respective league). He went on to win the next seven Gold Gloves.
Shantz left baseball with a 119-99 with 48 Saves.