He averaged 12.4 points, 6.4 rebounds, 3.3 assists and 1.4 blocks while playing 55 regular-season games with Houston, which picked him up when he was waived by Detroit after 28 games last season.
Smith reportedly signed a one-year deal for the veteran minimum worth $1.5 million.
He helped the Rockets rally from a 3-1 series deficit against the Clippers in the Western Conference semifinals. Smith scored 19 points in Game 6, when the Clippers led by 19 points at home only to lose. He had 15 points in Game 7.
The 29-year-old forward is the 25th player in NBA history with over 10,000 points, 5,000 rebounds, 2,000 assists and 1,000 blocked shots.
The signing was announced Thursday.