Conor Sims Jackson (born May 7, 1982, in Austin, Texas), nicknamed Co-Jack, Throw-Jack, Action, and Schooner Jinx, is a first baseman in Major League Baseball who plays for the Arizona Diamondbacks. He bats right-handed and throws right-handed. He is 6' 2" and roughly 225 pounds. His father is actor John M. Jackson, who portrayed Admiral Chegwidden on the show JAG.

After graduating from El Camino Real High School in Woodland Hills, California in 2000, Jackson proceeded to have a stellar collegiate career at the University of California (Berkeley) as a third baseman. He developed a reputation for a patient batting eye and led the Pac-10 with a .538 OBP in 2003. Jackson was drafted in the first round (19th overall) of the 2003 MLB amateur draft.

Never known for his defense prowess, Jackson was moved to the outfield shortly after being drafted. In his initial debut with Yakima of the shortseason Northwest League, he batted .319 with a league record 35 doubles. After his minor league debut, Jackson successfully climbed the minor league ladder. After fielding only .964 in the outfield in the minors, he was moved to first base, where his defensive struggles continued.