Schmidt, Ramon Troncoso, George Sherrill and James McDonald combined on a three-hitter. McDonald retired the final six batters.
Ethier hit a three-run homer in the fifth off Tommy Hanson (5-2) and added a run-scoring double in the ninth.
Schmidt (2-1), who played for the Braves in 1995 and '96, walked five and struck out three in six innings, his longest start since going six innings for the Dodgers at San Diego on June 5, 2007. The right-hander made his third start of the season after missing 2008 following surgery on his right shoulder.
Sherrill, acquired from Baltimore on Wednesday, struck out the side in the seventh in his debut with the Dodgers.
After Troncoso gave up singles to Diory Hernandez and pinch-hitter Greg Norton, Sherrill struck out Nate McLouth and Kelly Johnson before walking Chipper Jones to load the bases. Sherrill got Brian McCann on a called third strike to end the inning.
Jones' third-inning single was the only hit off Schmidt.
Hanson gave up eight hits and four runs in six innings to lose his second straight start.
Russell Martin and Rafael Furcal reached on fifth-inning singles before scoring on Ethier's homer.
Ethier leads the Dodgers with his career-best 21 homers. He passed James Loney for the team lead with 65 RBIs.
Orlando Hudson walked and scored on Furcal's single in the seventh, pushing the lead to 4-0.
Manny Ramirez was 1 for 4 with two strikeouts on the one-year anniversary of his trade to Los Angeles from Boston.
NOTES: Braves manager Bobby Cox said OF Ryan Church (elbow) and SS Yunel Escobar (bruised right wrist) were unavailable. 2B Martin Prado (bruised left ankle) did not start and hit a deep fly ball to center in the ninth as a pinch-hitter.