Unger enrolled in the University of Oregon, where he played for the Oregon Ducks football team from 2005 to 2008. While playing for the Ducks, Unger was twice named as a first-team All-Pac-10 selection, and also receiving honorable mention and second-team All-Pac-10 honors. He was a first-team All-American in 2008 in recognition of his successful season. Unger started on the offensive line in all of his four years with the Ducks.
Projected to be second round selection, Unger was listed as the No. 1 offensive guard available in the 2009 NFL Draft. He was described as "not a great prospect," yet having "starting potential on the NFL level for years to come." Unger was drafted by the Seahawks in the second round with the 49th overall pick. He was the highest selected Oregon Ducks offensive lineman since Tom Drougas went 22nd overall in 1972.
Seattle Seahawks
Unger signed a 4-year contract with the Seahawks worth over $3 million on July 29, 2009. After a pre-season effort in which head coachJim Mora said "We believe he is ready to start and be a productive player in this league immediately," Unger was named starting right guard over Mansfield Wrotto. In 2012, Unger signed a four-year extension worth a maximum of $24 million making him one of the top 5 paid centers in the NFL. He was one of only three members to remain on the Seahawks from before John Schneider's arrival in Seattle in January 2010, along with Brandon Mebane and Jon Ryan. Unger won his first Super Bowl title with the Seattle Seahawks in Super Bowl XLVIII, beating the Denver Broncos by a score of 43–8. In 2013, he also made his second Pro Bowl team. In 2014, the Seahawks finished the season with a 12–4 record and made it back to the Super Bowl. The Seahawks failed to repeat as Super Bowl champions after they lost 28–24 to the New England Patriots in Super Bowl XLIX.
On March 10, 2015, Unger, along with the Seahawks' first round selection in the 2015 NFL Draft, were traded to the New Orleans Saints in exchange for tight endJimmy Graham. On May 8, 2017, it was reported that Unger suffered a foot injury and was expected to be out for five months and start the 2017 season on the PUP list. However the foot healed quicker than expected and was the Saints starting center for the entire 2017 season, starting all 16 games. Unger was named to his first Pro Bowl with the Saints and his third overall in 2018.
Retirement
On March 16, 2019, Unger announced his retirement from the NFL after ten seasons.