The Angels were done in by C.J. Wilson's lack of control. Wilson (6-5) walked a season-high five batters, including four in the third, in just 2 2-3 innings.
Josh Hamilton had a solo homer in the eighth inning in his return from the disabled list after breaking his left thumb on April 8. Fellow outfielder Mike Trout was back after missing two games with a stiff back, but left in the second inning with more back trouble.
Collin Cowgill replaced Trout and homered in the eighth.
Singleton walked and had two strikeouts and two errors at first base before he launched a towering shot off Matt Shoemaker into the bullpen in right-center in the eighth inning for his first major league hit to make it 6-2. Carter followed with his opposite field shot to the seats in right field to give Houston back-to-back homers for the first time this season.
Wilson walked three of the first four batters in the third inning to load the bases. Castro followed with his single to right field to put Houston up 2-0. Matt Dominguez singled to load the bases again and Wilson walked Singleton on four pitches to give the rookie his first career RBI.
He struck out Carter for the second out before Grossman's full-count single drove in two more to stretch the lead to 5-0 and chase Wilson.
Houston starter Collin McHugh (4-3) allowed two hits over five scoreless innings to lower his ERA to 2.52.
Singleton, a highly touted prospect expected to help Houston back to respectability, made his major league debut a day after agreeing to a five-year, $10 million contract. Fellow young talent George Springer, who was called up in April, stood up in the dugout cheering and yelling as the 22-year-old Singleton rounded the bases on his homer.
The players danced and laughed together when Singleton returned to the dugout, a rare scene in recent years as the Astros plummeted to Major League Baseball's basement.
Singleton served a 50-game suspension last season for a second violation of a drug of abuse. He told The Associated Press in spring training that he has an addiction to marijuana and had spent a month in a rehabilitation center last year. He moved past his problems this season and got the call to the majors after hitting .267 with 14 homers and 43 RBIs for Triple-A Oklahoma City.
He said before the game that Tuesday meant even more because of his past struggles.
“It's definitely been a work in progress every single day that's been leading up to today,” he said “Today is one of the happiest days of my life.”