Braun, the reigning National League MVP, belted a pair of homers off Joe Wieland and another off Ernesto Frieri before adding a two-run triple in the ninth for good measure. His 15 total bases set a team record.
"It's an extremely challenging game that we play. You know you are going to deal with a lot of failure and a lot of adversity," said Braun. "When you have a special night like that you try to enjoy it and it's that much more fun and enjoyable when your team wins the game."
Alex Gonzalez had a two-run double for the Brewers, whose starter, Randy Wolf (2-2), was credited with the win after allowing three runs on nine hits and three walks over five-plus innings.
Wieland (0-4) remained winless in his young big-league career after yielding five runs -- three earned -- on five hits in his five-inning start.
"This was a great learning experience for me," said Wieland. "A great hitter like (Braun) is going to make adjustment pitch to pitch and at-bat to at-bat."
San Diego, coming off consecutive losses to the Giants, pushed the first run across on Yonder Alonso's RBI single in the second inning.
Braun countered with an opposite-field solo homer in the fourth, and Gonzalez doubled in Aramis Ramirez and Mat Gamel later in the frame.
The Padres nearly tied the game in the bottom half, as Jason Bartlett hit one off the left-field wall to plate Orlando Hudson. Alonso also tried scoring on the double, but was thrown out at home on a perfect relay throw.
Braun homered again in the fifth, this time golfing a two-run moonshot that found its way into the upper deck down the left-field line. Rickie Weeks walked before the blast.
San Diego stayed within striking distance on Bartlett's run-scoring double- play ground ball in the sixth, but Braun answered again in the seventh.
The slugger's line drive into the first row of seats in left field capped the first three-homer game in the pitcher-friendly park's nine-year history. It was also the first such game of his career.
Braun came up again in the ninth with a chance to become the 16th player in MLB history to record four home runs in the same game, but instead hit a gapper to right-center that knocked in Weeks and Nyjer Morgan.
Braun, who entered the game with four home runs on the season, tied a career- high with six RBI. He has 13 career multi-home run games...Chris Denorfia had two hits and two walks for the Padres, who outhit the Brewers, 9-7...Milwaukee improved to 2-2 on its current nine-game road trip.