The Mets drafted Jeff McKnight in the 2nd round of the 1983 amateur draft. After spending 7 seasons in the minors he finally made his Major League debut on June 6, 1989 against the Chicago Cubs In his first Major League at bat as a pinch hitter for Roger McDowell. he singled. The next day he made his first career start. As the Mets starting 2nd baseman he went 1 for 2 with 2 walks as the Mets beat the Cubs 10-8. McKnight appeared in 6 games before being sent back to the minors. He batted .250 (3 for 12) while playing all 4 infield positions.
Following the 1989 season McKnight was released by the Mets and he was picked up by the Baltimore Orioles. He returned to the Mets as a free agent on December 21, 1991. He started the 1992 season in the minors before getting recalled in August. He appeared in 31 games playing in both the infield and outfield and batted .271 with 2 home runs and 13 RBIs. His first home run came on September 15, a two-run shot that propelled the Mets to a 4-2 win over the Cubs.
McKnight spent the entire 1993 with the Mets serving as a utility player and pinch hitter and appeared in 105 games. He hit .256 with 2 home runs and 13 RBIs. He started the 1994 season with the Mets and was used exclusively as a pinch hitter but hit just .148 (4 for 27) with 2 RBIs. He was sent back to the minors in June. He returned in August and appeared in one game on August 11 against the Philadelphia Phillies. He hit a pinch-hit single in 7th inning. It would be his last appearance in a Major League uniform and his last hit. The next day the players went on strike and would not return until 1995.
He was granted free agency following the season but did not sign with another team. In 173 career games for the Mets McKnight hit .250 with 4 home runs and 28 RBIs.
While with the Mets McKnight wore number 15 in 1989, number 5 in 1992, numbers 7 and 17 in 1993 and number 18 in 1994.
Jeff McKnight also played for the Baltimore Orioles in 1990 and 1991