The actor was found dead in his LA home on Tuesday morning by his girlfriend. US reports have claimed the star was out drinking with friends the night before.
His lawyer Richard Kaplan commented: "He was working hard on his sobriety. He was doing well. He was a nice person."
Renfro made his movie debut in Joel Schumacher's The Client in 1994 and went on to star in such films as Apt Pupil, Sleepers and Ghost World.
The Hollywood Reporter awarded him the 'Young Star' award at the age of 12 for his role in The Client.
Renfro's career suffered due to drink and drug problems and in May 2006 he was forced to spend 10 days in jail for attempting to purchase heroin from an undercover police officer in LA.
He had recently completed work on Bret Easton Ellis adaptation The Informers, which stars Tommy Lee Jones and Winona Ryder.