Norton was fired by the Seahawks in January after four seasons in charge of Pete Carroll's defense. Norton previously had been the Oakland Raiders' defensive coordinator for three years before reuniting with Carroll, his boss at Southern California from 2004-09.
Norton was a star linebacker at UCLA from 1984-87, leading the Bruins to four bowl games and the 1985 Pac-10 championship. He went on to become the only player in NFL history to win three consecutive Super Bowls.
Norton will work with Bill McGovern, who became Kelly's defensive coordinator in February. McGovern, the Chicago Bears' inside linebackers coach last season, coached under Kelly with the Philadelphia Eagles.