James Jones added 10 for Miami in place of star guard Dwyane Wade, sidelined a second straight game with a sore hamstring. The Heat also played without Ray Allen and Mario Chalmers.
It didn't matter against the team with the NBA's worst record. Milwaukee tried to match Miami's energy, but couldn't keep with the more talented opponent - even one without two All-Stars.
Defense keyed Miami's win. The Heat led 46-29 at halftime and held the Bucks to a season low for points in a half and in a game.
John Henson had 12 points and 10 rebounds for Milwaukee.
On paper, this was a mismatch from the opening tip - the two-time defending NBA champions against a young, undermanned squad that fell to 14-59 on the season.
But the Heat at times played a bit disheveled, perhaps a little worn from their third straight road game and fourth in five contests.
James extended his consecutive-game streak of double-digit scoring to 564, the fourth-longest run in NBA history. But James only got to 10 with about 5:16 left in the third quarter on a 3.
Fresh off recording a triple-double in a 110-78 blowout win Friday night in Detroit, James had nearly as many turnovers (three) as points (four) in the first half. His two early buckets, though, came off open dunks that thrilled the crowd, a few of whom were wearing James jerseys.
Miami opened the game 3-of-14 from the field. The shooting improved, and the Heat clamped down on the other end and held the Bucks to 12-of-39 shooting (30 percent) in the first half, and 34 percent for the game.
The Heat held an opponent under 40 percent shooting for the fourth straight game, and ended their road trip with two straight wins after losing Wednesday in Indiana.
Just like Friday night, James spent the fourth quarter on the bench with a victory well in hand. The only drama in the second half when James would get to double digits in scoring.
A dunk with 6 minutes left in the third gave Milwaukee a 54-38 lead. Khris Middleton missed a jumper, and James corralled the rebound before spotting up at the wing for his 3 to get to double figures.
Zaza Pachulia and Udonis Haslem exchanged buckets before Pachulia missed a jumper with about 4 minutes left. James got the rebound and then threw a long outlet pass to streaking Haslem down court for a layup.
James clapped, slapped his right hand on his thigh and waited down court on defense. His night was just about over.
Ramon Sessions had a game-high 15 points for Milwaukee, while Toney Douglas and Rashard Lewis each added 13 for the Heat.
Bothered by a sore hamstring, Wade watched in a gray suit and white sneakers in returning to the arena in which he played college ball at Marquette.
NOTES: Allen, sidelined with a stomach virus, played in Milwaukee from 1996 through part of the 2002-03 season. He holds the franchise record for most 3-point field goals in a game at home with 10. ... Chalmers missed the game with a bruised quad, and Greg Oden was also sidelined by back spasms.... The Bucks have yet to win consecutive games all season. They were coming off a 108-105 win Thursday over the Lakers.