Gruden, 52, was fired by Redskins in October after the team started the 2019 season with an 0-5 record. The Jaguars ranked fifth in points and sixth in yards in 2017, but have slipped in the two years since.
Jacksonville ranked 31st in points in 2018 and 26th in points in 2019. The Jaguars fired offensive coordinator John DeFilippo on Jan. 13, after just one season. Jacksonville fired offensive coordinator Nathaniel Hackett in 2018 after he helped coach the offense for three seasons.
"In going through the search process, it was important to me and our staff to identify a candidate who had a clear and concise vision for how to lead our offense and how to get the most out of our players and assistant coaches," Marrone said.
"I believe that coach Gruden is the right person for what we need right now and the direction that we want to take our offense."
Gruden served as the offensive coordinator for the Cincinnati Bengals for three seasons before becoming coach of the Redskins in 2014. The Bengals offense ranked sixth in points during Gruden's 2013 campaign with the team. The Bengals also ranked third in passing scores and went 11-5 to win the AFC North in 2013.
Gruden posted a 35-49-1 record in 85 games with the Redskins. The Redskins offense ranked third in yards and 12th in points in 2016. Washington ranked 10th in points in 2015, after finishing 26th in points in Gruden's first season. Washington ranked last in points in 2019.
"During the interview process, it became very clear that coach Gruden learned a lot from his experience as a head coach and he's ready to get back to work," Marrone said.
Gruden began his coaching career as a student assistant at Louisville before several stops in the AFL. He got his first shot in the NFL under brother Jon Gruden in 2002 with the Tampa Bay Buccaneers. Gruden coached the UFL's Florida Tuskers before taking the Bengals offensive coordinator job in 2011.