Smoltz (1-1), relying more on a changeup he says he threw about 25 times, recorded his 16th career shutout and 51st complete game.
"This is the type performance I expect," said Smoltz, who earned the first victory by an Atlanta starter this season.
The Braves starting staff began the day with the worst ERA in the major leagues.
"I would say normally it's no big deal but when you've dealt with what we've dealt with over the last week and a half ... this hopefully will get guys thinking more positively," Smoltz said.
Peavy (1-2) gave up only four hits and two runs in seven innings as the Braves were held under four runs for the first time this year. He struck out eight batters and issued two walks, one intentional.
"Against John Smoltz, you have to be really good to win," Peavy said. "I wasn't good enough."
Smoltz walked two batters in his first shutout since June 21, 2005, a 5-0 win over Florida. He pitched his first complete game since June 26, 2005, against Baltimore.
"It was a well-pitched game on both sides," said Padres manager Bruce Bochy. "(Smoltz) was on the top of his game. He threw great. We didn't get many opportunities."
Braves manager Bobby Cox said the 2-0 score "was indicative of the way both guys pitched, which was outstanding."
The Braves needed the strong start by Smoltz. Through their first 11 games, no Atlanta starter had a win and they had an 8.17 ERA to rank last in the majors.
"Statistically there was no way they could keep doing what they had been doing the first week and a half of the season," said Adam LaRoche, who gave the Braves a 1-0 lead with his second-inning home run. "It was gonna turn. It was just a matter of time."
It is the first time in franchise history the Braves played their first 11 games without a win from a starting pitcher.
"This broke the ice," Smoltz said. "It's been a storyline for a while and it's an interesting one because it's never happened before."
But the Braves stayed close to .500 by leading the majors with 74 runs through 11 games. They set another franchise first by scoring four or more runs in each of the first 11 games.
After all the early season offense, the Braves finally returned to their one constant of the last 15 years.
Smoltz, the only player left on the roster from the 1991 team that started the string of 14 straight division championships, was the logical choice to provide the Braves' first quality start.
Smoltz allowed only one baserunner past second base. In the third inning, Peavy reached on an infield hit, moved to second on Dave Roberts' bunt and advanced to third on a long fly ball to center by Termel Sledge. But Brian Giles lined out to right field to end the inning.
Smoltz had the help of some strong defensive plays, especially in the outfield. "Our defense won the game," he said.
Later in the inning, Jones had to race to the warning track to catch up with a long drive hit by Peavy. Still running at full speed, Jones had to reach up for the catch.
"Andruw ran down everything he could run down, and then some," Smoltz said.
After LaRoche's third homer of the year, Peavy gave up only one more hit -- a third-inning single by Edgar Renteria -- until the seventh inning.
Peavy hit Jones with a pitch to lead off the inning. He stole second and moved to third on an infield hit by LaRoche. Jeff Francoeur followed with an RBI single.
With one out and runners on second and third, Peavy issued an intentional walk to load the bases. Peavy struck out Smoltz on three pitches and ended the inning on Marcus Giles' fly ball to center.
- Rookie Tony Pena replaced Renteria at shortstop to open the seventh inning. Renteria appeared to grimace in pain while swinging in the bottom of the sixth inning. He suffered a strained rib cage and is day to day.
- LaRoche hit his first homer since April 4.
- Josh Barfield stole his third base of the season in the fifth inning.