Jackson, an offensive guard from Mississippi State, was selected 81st overall by the Raiders in May.
Jackson is expected to be a key piece of the Raiders offensive line and could battle for a starting job as early as this season.
With this signing, the Raiders now have all eight of their 2014 NFL Draft picks under contract and ready to go.
In addition to signing Jackson, the Raiders made additional acquisitions Thursday by announcing the signings of wide receivers David Gilraeth and Rashaan Vaughn, to go along with singing K/P Michael Palardy.
Gilraeth has been with the Steelers, Buccaneers Bills, Rams and Colts but has only played in three career games, primarily on the special teams units.
Vaughn spent a brief time with the New York Jets practice squad before being waived, but is from Oakland, Calif.
Palardy is joining the Raiders as an undrafted free agent out of the University of Tennessee.