John Kruk was raised in Keyser, West Virginia in Mineral County, the state's Potomac Highlands. He played baseball at Keyser High School in Keyser, West Virginia, at Potomac State College, and at Allegany Community College, He began his professional career with the San Diego Padres after being drafted in 1981.
He was dealt to the Philadelphia Phillies during the 1989 season, and he blossomed into an All-Star as the team used him primarily at first base. Kruk played in the All-Star Game in 1991, 1992, and 1993. Moving to the American League to serve as a designated hitter, Kruk signed with the Chicago White Sox after playing for the Phillies. On July 30, 1995, in a game at Baltimore's Camden Yards stadium, Kruk singled and took himself out of the game. He left the ballpark never to play again. He finished his 10-year career with exactly a .300 batting average and exactly 100 home runs.
A quotable character throughout his career who later wrote a book called I Ain't an Athlete, Lady published in 1994, Kruk turned to broadcasting and commenting on the game. He has since worked for FOX, The Best Damn Sports Show Period, and in 2004, he was hired by ESPN as an analyst on Baseball Tonight.
Kruk coached the National League team in the Taco Bell All-Star Legends and Celebrity Softball Game in 2010. He also was also a commentator on the video game MLB 2k10, 2k11, and 2k12.