James stormed out of the gate in his sixth contest back in Cleveland, scoring 25 of his 43 points in the opening quarter for the Heat at Quicken Loans Arena on Tuesday night.
The 29-year-old tallied 16 points before missing a shot and drained his first four shots from beyond the arc.
He was 10-of-11 from the floor and knocked down five of his six tries from three-point range in the first quarter.
James finished with 31 points in the first half and 14-of-19 from the field for the game to go with six rebounds and four assists for Miami, who have won two in a row after a 1-5 tailspin.
Chris Bosh had 12 of his 21 points in the fourth quarter in the triumph.
Dion Waiters finished with 17 points and 11 assists for the Cavaliers, who were playing their first game without star Kyrie Irving. Cleveland has dropped six of their last eight games.
All-Star game MVP Irving will miss at least two weeks with a left bicep injury suffered in Sunday’s loss to the Los Angeles Clippers.
Miami have won all three contests this season with Cleveland and are 13-1 against the Cavaliers since James left for south Florida in the summer of 2010.