Kessinger accepted a $25,000 bonus to sign out of the University of Mississippi. With Ernie Banks, Glenn Beckert, and Ron Santo, he gave Chicago an all-star infield. Though he led the NL in errors in his first season as a regular (1965), Kessinger quickly established himself as an outstanding fielder, leading league shortstops in putouts three years, assists four years, double plays four years, and fielding average once. He played 54 straight errorless games in 1969, then the record for shortstops, and started for the NL in five All-Star games. He was a pesky, reliable hitter, with a top average of .274 in 1966 and 1972. On July 17, 1970 he went 6-for-6 in a 10-inning game. The clean-living Kessinger served as player-manager for the White Sox in 1979.