Gallardo hit one of five home runs for Milwaukee, which went back-to-back twice in a 10-4 rout of the Pittsburgh Pirates on Monday night.
The right-hander also tossed three-hit ball over seven innings, retiring his final 13 batters while improving to 10-2 against Pittsburgh. Gallardo and Norichika Aoki hit consecutive homers in the fourth before Carlos Gomez and Yuniesky Betancourt repeated the feat in the fifth.
"We came out really aggressive. Today, everyone was swinging good," Gomez said. "One through nine, even the pitchers, we can drive the ball."
Jean Segura also connected for the Brewers, who added three triples and matched a season high for runs. They finished with nine extra-base hits and hit back-to-back homers twice in a game for the first time since 2005.
A day earlier, Dodgers ace Clayton Kershaw retired 18 consecutive batters and struck out 12 in eight dominant innings for a 2-0 victory over Milwaukee.
"We turned the page today," said Segura, who hit a two-run shot in the first inning. "I feel great at the plate right now. I'm relaxed and having fun."
Milwaukee is 45-7 against the Pirates at Miller Park since 2007, the best record by any team against a division opponent during that stretch.
"They play well here. You've got to do some things different than we did tonight to slow down the offense. We didn't," Pittsburgh manager Clint Hurdle said. "We weren't able to execute any part of our game plan. Zero."
Gallardo (3-1) struggled with his command early but managed to settle down. He gave up two runs, one earned, struck out five and walked two.
"The last start in San Diego I struggled a little bit. I had to fight for it. Today, in the first few innings, it was the same scenario but the difference today is that I was able to make an adjustment. As the game went on I was able to find that rhythm," Gallardo said.
Brewers manager Ron Roenicke was glad Gallardo was able to get deep in the game.
"I was looking up after three innings and he's got 60 pitches or some pretty high number," Roenicke said. "I thought he struggled with his command early. Then he got the rhythm and started throwing strikes and finished outstanding."
The Pirates jumped out to a 1-0 lead in the first, but Milwaukee went ahead in the bottom half on Segura's two-run shot. The Brewers added three more runs in the inning as Pittsburgh starter Wandy Rodriquez (2-1) struggled with his control, issuing four walks.
Rodriguez, who entered with a 1.66 ERA, had walked only three batters in his first four starts of the season.
"I had bad location. A lot of hitters I started behind in the count," Rodriguez said. "For the hitter, it's easy when they know what's coming. When you're behind you throw a fastball for a strike and they know a fastball is coming and they hit it."
The left-hander lasted 3 2/3 innings, giving up six hits and seven runs. He walked four, struck out two and gave up three homers.
"His fastball command wasn't what he wanted," Hurdle said. "We weren't able to spot the ball, get the ball where we wanted. The breaking ball didn't come into play until it was way too late. The changeup really wasn't a factor. So you're going out there without the three weapons you normally take. You're leaving balls in the middle of the plate and you get bad results."
The Pirates added a run in the third inning as they benefited from a double error by Milwaukee first baseman Martin Maldonado, who misplayed a grounder and then made an errant throw, allowing Garrett Jones to reach second base. Jones scored on Gaby Sanchez's double.
Solo home runs accounted for the next four Brewers runs as they extended the lead to 9-2 after five innings. Milwaukee added a run in the seventh when Betancourt singled to drive in Gomez, who led off with a triple.
Jones hit a two-run homer in the eighth for the Pirates.
Brewers first baseman Corey Hart, who hasn't played this season, returned to Milwaukee to continue his rehabilitation from January knee surgery. Hart had been working out at the Brewers' complex in Phoenix. ... The Brewers hit at least three triples in a game for the eighth time in franchise history. ... Marquette men's basketball coach Buzz Williams threw out the first pitch. The Golden Eagles, who reached the Elite Eight in this year's NCAA tournament, were recognized in a pregame ceremony.