Andruw Jones had two hits, including his major league-leading 24th homer, and drove in two runs. Smoltz (8-5) won his fourth straight start, giving up five hits while lowering his ERA to 2.74.
The Braves completed a three-game sweep and a 5-1 homestand, during which Andruw Jones had five homers and 11 RBI.
"I said it a while back, Andruw is going to have to carry us, and he has," Smoltz said. "He's striking fear into the other teams' pitchers."
Since Chipper Jones went on the disabled list with a foot injury June 6, Andruw Jones has hit .382 with 12 homers and 23 RBI.
"He's a problem for everyone, his numbers prove that," said Rafael Palmeiro, who provided Baltimore's only run with his 11th homer in the fifth inning for the Orioles' first hit.
Palmeiro's 562nd home run left him one behind Reggie Jackson for ninth on the career list.
Rookie Brian McCann had three hits and two RBI for Atlanta, which also has pitchers Tim Hudson, Mike Hampton and John Thomson on the disabled list. Rafael Furcal added two hits, including a two-run triple.
Smoltz opened with four perfect innings and improved to 5-1 in June with his 50th career complete game and third this year. He has pitched at least eight innings in five straight outings.
The right-hander struck out seven and walked none for his third complete game in four starts. He threw a five-hitter in a 5-0 victory over Florida last Tuesday, his first shutout in six years.
"Early on I lost a lot of games in the eighth inning," Smoltz said. "These last five games have been big because I haven't lost in the eighth inning."
The 38-year-old Smoltz earned 154 saves as Atlanta's closer before returning to the rotation this year.
"He's great," Palmeiro said. "He's a great pitcher. He gets great results."
Smoltz capped the Braves' four-run eighth inning off reliever Steve Reed with a run-scoring double for his first RBI since June 29, 1999, at Montreal.
Rodrigo Lopez (7-3) gave up seven hits and four runs in six innings, ending his streak of five straight wins since his previous loss on May 19 at Kansas City.
Furcal led off the first inning with a single. After his NL-leading 25th stolen base, he scored on Andruw Jones' single.
The Braves added two runs in the second for a 3-0 lead. Following singles by Ryan Langerhans and McCann, Furcal hit a two-out triple to right.
Andruw Jones' homer, estimated at 431 feet, pushed the lead to 4-1 in the sixth.
Marcus Giles hit an eighth-inning double off Reed. After Andruw Jones struck out and Adam LaRoche was intentionally walked, Giles scored on a one-out single by Wilson Betemit. Langerhans' single loaded the bases, setting up a two-run single by McCann.
Smoltz chased Reed with his double to the right-field wall.
- Smoltz struck out the side in the eighth, giving him 2,487 strikeouts to pass Don Drysdale for 27th place on the career list.
- Furcal's triple was his sixth of the year, moving him into a tie for second in the NL. He led the NL with 10 triples in 2003.
- Betemit stole his first base of the season, and second of his career, in the sixth.