The Rockets formally introduced the versatile forward on Wednesday, after he signed a multiyear contract.
The 24-year-old free agent agreed to join the Rockets last Thursday night, switching places with free agent Ron Artest, who left Houston to play for the Lakers.
"I think this was the best place for me," Ariza said. "I think I have more of an opportunity."
The 6-foot-8 Ariza averaged 8.9 points and 4.3 rebounds and shot 32 percent from 3-point range for Los Angeles in the regular season. He raised his stock during the Lakers' championship run, averaging 11.3 points, 2.3 assists and shooting 47.6 percent from 3-point range.