The Cavaliers scored five straight points -- four by Zydrunas Ilgauskas -- to increase their lead to 96-89 with 6:13 to go in the fourth quarter, but two free throws by Chris Bosh and a three-pointer by Jason Kapono drew Toronto within 104-103 with 57.1 seconds remaining.
James hit a turnaround jumper with 16.7 seconds left to seal the Cavaliers' second straight victory. He finished with 37 points, 12 rebounds and 12 assists.
Chris Bosh led Toronto with 41 points, four rebounds and five assists.
Kapono came off the bench to score 17 points, and Andrea Bargnani had 14 points and five rebounds for the Raptors, who have lost three of four.