James scored 23 of his 36 points in the second half and the Cavaliers held a double-digit lead for much of the fourth quarter.
Los Angeles’ Kobe Bryant cut the deficit with two free throws after being fouled on a three-point attempt, but James sealed the win with a driving layup.
In Houston, guard James Harden produced a fine individual display for the Rockets in their 112-101 win over the Oklahoma City Thunder.
Harden picked up 31 points, 10 assists and nine rebounds as the Rockets (28-12) placed all five starters plus reserve forward Josh Smith in double figures.
The Thunder struggled to recover from a sluggish start, allowing Houston to open up a 40-18 lead in the first quarter.