Jacksonville announced the hire Tuesday.
"Dom Capers is one of the most respected defensive coaches in the game today, and he has been for many years," Jaguars coach Doug Marrone said in a news release. "His defenses have long been among the most effective and productive in the NFL.
"He has career experiences and accomplishments that will benefit our coaches and our players. He adds a unique perspective and veteran presence that will be valuable assets to immediately help us. I look forward to working with Dom and having him on our staff."
Capers, 68, was the Packers' defensive coordinator from 2009 through 2017. He also has head coaching experience, posting a 48-80 record in eight seasons with the Carolina Panthers and Houston Texans. He entered the NFL coaching ranks in 1986 as a defensive backs coach for the New Orleans Saints. Capers also held defensive coaching roles with the Pittsburgh Steelers and Miami Dolphins.
He was the Jaguars' defensive coordinator in 1999 and 2000.
The Packers fired Capers on Jan. 1, 2018, and went on to hire Mike Pettine. Todd Walsh has served as the Jaguars' defensive coordinator since 2016.
Jacksonville had the fifth-best defense in terms of yards allowed in 2018 after ranking second in 2017.