James' key shot with 15.1 seconds left enabled the Heat to post a second win in two games over the Magic. They won 120-92 Wednesday in Orlando.
James also provided nine rebounds and seven assists. Dwyane Wade added 27 points for Miami, which win a sixth straight overall.
Chris Bosh scored 15 points.
Glen Davis put in 20 points in his first game for the Magic since Jan. 20 following two operations to repair a broken left foot.
Arron Afflalo added 18 points and seven rebounds, and Victor Oladipo had 17 as the Magic fell for the sixth time in seven games.