Macdonald has spent seven years with the Ravens, three in his role coaching the linebackers, and worked in various roles at Georgia from 2011 to 2013.
"It is an honor to join Coach Harbaugh's staff at the University of Michigan," Macdonald said in a statement. "I firmly believe in his vision and am excited to get to work. Our staff will work tirelessly to develop our young men both on and off the field -- I cannot wait to meet and develop relationships with our players, staff, and community! [Fiancée] Stephanie and I are excited to join the Michigan family, and we are very thankful for this opportunity -- Go Blue!"
Macdonald had been working under coach Jim Harbaugh's brother, John, in Baltimore, so there is some familiarity there. At 33 years old, Macdonald is bringing a youthful presence to the Wolverines' defensive staff.
He is replacing Don Brown, who had held the job for five seasons. Brown was let go after Michigan finished 2-4 in 2020 and ranked 89th by giving up 434.3 yards per game.
It's unknown as of now what defensive assistant positions will be filled by Macdonald, but he is the second addition to the staff, as the Wolverines recently announced Mike Hart as the running backs coach.
"Mike is an excellent defensive mind who is highly respected across the NFL," Jim Harbaugh said in a statement. "He has been a valuable member of the Baltimore Ravens staff, and shown a passion for teaching, coaching and developing his players. We are excited about everything that Mike brings to our defense, team and university."