Hobby had coached under Duke coach David Cutcliffe during Cutcliffe’s entire tenure as coach at Ole Miss.
Hobby was on Sean Payton’s staff in New Orleans for the past two seasons, joining the Saints after a season at Clemson and six seasons at Mississippi.
Duke defensive coordinator Mike MacIntyre is in charge of generating a game plan and calling plays on Saturday. Hobby will coach the defensive line and help MacIntyre with the weekly plan.
Hobby, an Irondale, Ala., native who was recruited by Cutcliffe at Tennessee, comes to Duke with experience coaching under Cutcliffe, as well as experience coaching in the ACC.
“The first thing to know about Marion is that he is a winner,” Cutcliffe said. “He played for great people in high school. He has a great understanding of the game and is an exceptional leader of young men. Marion is the finest defensive line coach in America.”