The Big Reds took control with a 16-6 edge in the first quarter. They led 30-18 at halftime and 44-31 after three quarters.
Edriese Jenkins led a balanced Muskegon attack with 16 points and seven rebounds. Eonte Tornes added 14 points while Clinton Jefferson Jr. had 11 points, five steals and three assists.
Willie Shanks grabbed nine rebounds for the Big Reds.
Jason Whittaker paced Rockford with 19 points.