The 20-year-old was third on the team with 73 tackles, his 13 tackles for loss were the most on the team this season and he tallied 1.5 sacks. He will join cornerback Jalen Collins and linebacker Kwon Alexander, both juniors, and become the third LSU player to declare for the draft this year.
He revealed his decision with a Twitter message thanking the school, team and fans.
Hunter will be the 19th LSU player to leave early in the last two seasons.
Aided by Hunter, the LSU defense allowed 17.5 points and 316.8 yards per game, finishing ninth in the FBS in total defense. The team finished 8-5 overall and 4-4 in the SEC, losing 31-28 to Notre Dame in the Music City Bowl.
The 2015 NFL draft is scheduled for April 30-May 2. ESPN analyst Todd McShay has said that Hunter, as well as Alexander and Collins, are likely to be taken on the second day.