The 6-foot-10, 300-pound center withdrew his name from consideration for the NBA draft after taking part in Saturday's combine at the Nets' practice facility in East Rutherford, N.J.
"It was great to go through this process and have the chance to talk to some teams," Johnson said. "I got positive feedback about my hands and footwork, but I decided that it would be best for me to come back to school and continue to work on some things to get to that next level.
"I feel like we have a great team returning next year, and I want to work with my teammates at Miami to make the NCAA tournament. The opportunity to do that is a big part of my decision to come back."
Johnson, who averaged 11.9 points and 9.6 rebounds per game, will play under new Miami coach Jim Larranaga.
"We're very happy that Reggie has decided to return to our program at Miami," Larranaga said. "I'm looking forward to working with him and his teammates to win an ACC championship and compete in the NCAA tournament. Reggie is a big, strong man who we expect to anchor both our offense and defense next season."