Jackson recorded three tackles and a sack in Sunday's 28-26 win over the Steelers.
Jackson had increased responsibility since the Seahawks' defensive line was battling injuries in the form of DT Poona Ford (calf) and DE Ezekiel Ansah (shoulder). He performed well, recording the team's only sack while playing 37 of 57 defensive snaps (65 percent). His chances will likely be limited once Ansah returns, which could be Week 3 versus the Saints.
Jackson signed his exclusive rights free agent tender with the Seahawks on Monday, Josh Boyle of the team's official site reports.
Jackson played in a rotational role on the defensive line on and off throughout the 2018 season, with his highest snap count (40) coming Week 13 against the 49ers. In the end, he totaled 10 tackles (nine solo) and a sack across nine games. He'll look to cement himself as a depth option once again in 2019.
Jackson agreed to a contract with the Seahawks on Tuesday, Bob Condotta of The Seattle Times reports.
Jackson was promoted from the practice squad and will presumably provide depth at defensive end. He tallied just 11 tackles (seven solo) and a half-sack across 12 games with Seattle last year.
Jackson made four tackles (two solo) in Thursday's 19-17 preseason loss to the Colts.
Jackson played 12 games for the Seahawks in 2017 and recorded 11 tackles and 0.5 sacks. When the defensive corps is healthy, Jackson will be a backup to Dion Jordan (shin). However, Jordan may not be ready for Week 1, so Jackson and rookie Rasheem Green will battle for the starting job.
Jackson was promoted to the Seahawks' 53-man roster Saturday.
Jackson's promotion is no surprise as the Seahawks defensive line was looking extraordinarily thin with Cliff Avril (neck) and Quinton Jefferson (hand) both looking at prolonged absences. The 24-year-old takes the roster spot of linebacker Justin March-Lillard, and will likely play a similar role to Marcus Smith as a rotational defensive end.