CHICAGO -- Lucas Harrell made the big pitches when he needed to and let his teammates do the rest.
The result was a satisfying win over his former club.
Maxwell's two-run shot in the fifth inning put the Astros ahead 4-3. He also singled, walked and scored two runs. His homer was estimated at 461 feet, curling just inside the left-field foul pole into the second deck.
Altuve hit a two-run shot in the eighth for an 11-4 lead. He drove in three runs and stole home on the back end of a double steal in the sixth.
Martinez homered on first pitch of the second, and Wallace added a solo shot in a five-run sixth for Houston that broke the game open.
The Astros put up 20 runs in the three-game series -- 19 of them came in the two wins.
"It was huge to be able to put up that many home runs and get our first road (series) win," Astros manager Brad Mills said. "It was nice to see the guys come out swinging like that."
Harrell (6-4) tied a career high by going 7 1/3 innings, winning his first start against the team that let him go. He gave up five runs and six hits and struck out five.
The White Sox drafted Harrell in the fourth round in 2004, but waived him last July. Harrell has won four of his past five starts.
"I played with half those guys for two, three-plus years," Harrell said. "You know their tendencies, you know what they work on when they're in the cages. You go to those things and hopefully they're not hitting it."
Brett Myers got the last two outs for his 15th save.
White Sox starter Philip Humber (2-4), gave up the first three Houston homers, matching his career worst. He allowed six runs and six hits in 5 1/3 innings and struck out nine.
Humber had five straight strikeouts at one point spanning the third and fourth innings. He's 1-4 with a 7.50 ERA since throwing a perfect game on April 21 at Seattle.
"You look at it as kind of a wasted offensive day. It's frustrating when you score like that," White Sox manager Robin Ventura said. "It's like when you get a guy that pitches great and you don't score anything. You got to get them together."
Orlando Hudson brought Chicago within two with a three-run shot in the ninth, his first homer as a member of the White Sox. That drive chased Houston reliever Fernando Rodriguez before Myers finished the game.
Houston regained the lead on Maxwell's two-run shot in the fifth. The high, arching shot disappeared into a tunnel on the second deck. Ventura argued for an umpire review of the play, but the call wasn't reversed.
"I was hoping it was fair. I didn't even think about it until after Ventura came out," Maxwell said. "When I first hit it, I thought it was fair for sure."
Maxwell added a nice running grab at the wall in center on a long drive by Alejandro De Aza in the bottom of the fifth. He has six home runs in 93 at-bats this season. Houston claimed Maxwell off waivers on April 8 after the New York Yankees designated him for assignment.
Altuve became the first Astros player to steal home since Kaz Matsui did it on May 19, 2009, against Milwaukee. . The Astros acquired minor league OF D'Andre Toney from the Royals as the player to be named in a preseason trade that sent C Humberto Quintero and OF Jason Bourgeois to Kansas City for LHP Kevin Champman. ... Astros OF Jordan Schaefer sat out again with the same illness that kept him out of Saturday's game. Astros manager Brad Mills said Schaefer is also suffering from pink eye. . OF Carlos Lee (strained left hamstring) ran in a pool on Saturday and took batting practice on Sunday.