"Unfinished Business," Howard wrote in his Twitter announcement. "Looking forward to next season with this team."
Howard, a three-year starter, averaged 25 points, 3.9 assists and 4 rebounds for the Golden Eagles in 2018-19 and was named the Big East Player of the Year. He scored 53 points in an overtime win over Creighton on Jan. 10, breaking a Big East single-game record.
He was No. 87 on ESPN's ranking of NBA draft prospects, and No. 15 among point guards.
Marquette won 24 games last season but was knocked out of the NCAA tournament in the first round by Murray State.