Michael idolized Larry who, while not an NBA player, was a gifted basketball player at Emsley A. Laney High School in Wilmington and taught Michael many aspects of the game. Larry wore number 45 on his jersey, and that's what Michael originally wanted to wear once he got to high school. But since Larry was still playing there, Michael needed to choose a different number.
He instead chose to wear half of 45, which rounds up to 23. The number stuck, as he wore it throughout high school and college at the University of North Carolina, as well as most of his Hall-of-Fame NBA career.