James went 13-of-23 from the field and missed just one of his 16 foul shots, while playing after landing awkwardly on his left ankle in the first quarter. He also had four steals for the Cavs, who won their second straight game.
Delonte West added 16 points, and Zydrunas Ilgauskas was a force in the middle with 15 points and 10 rebounds for Cleveland, which won at home over the Bulls for the eighth time in the last 10 tries. Mo Williams had 13 points in the win.
Ben Gordon scored 31 in a reserve role for the Bulls, who lost their second in a row. Derrick Rose had 20 points and seven assists, and Luol Deng scored 18 to go with seven boards. Former Cavalier Drew Gooden logged 11 points and nine rebounds.
Seven straight points by the Cavaliers gave them a 17-13 early lead, and it was 30-24 going into the second. James was the driving force late in the first with seven points over the final 2:15.
Rose's layup had the Bulls within 47-43 with 2 1/2 minutes left in the half, but the Cavs finished the period on a 10-2 spurt, culminated by West's three- pointer off a cross-court pass from James. LeBron toyed with Gooden, moving his legs several times before delivering the pass to West, who nailed the shot from the left wing with 42.3 seconds left in the half.
A Deng jumper climbed Chicago within 65-58 with 5 1/2 minutes remaining in the third, but James took over with the final six points of an ensuing 10-0 run.
It was 83-71 going into the fourth quarter. Gordon's three-point play pulled Chicago within 90-83 with nearly seven minutes remaining, but James dominated again to pull Cleveland away. He first converted a three-point play, and then had two more buckets, including a tip-in for a 97-83 difference with 3:05 left.