Long, who ESPN's Mel Kiper projects as the No. 8 draft-eligible cornerback for 2019, announced his decision Wednesday on Twitter
Long led Michigan with eight pass breakups to go along with an interception and 17 tackles. He earned first-team All-Big Ten honors from the league's coaches this season.
The junior from Los Angeles started all 13 games in each of the past two seasons, earning honorable mention All-Big Ten honors in 2017.
Also, junior tight end Zach Gentry on Thursday became the fourth Michigan player to declare for the draft. He was third on the team with 32 receptions for 514 yards and two touchdowns this season.