The 50-year-old actor, who has battled addiction in his youth, is impressed that his son successfully completed a 20-month rehab programme.
"Congrats are in order for my firstborn, and I'm proud to oblige. Having braved the crucible of addiction (and pleased the court), his ongoing commitment to recovery continues to inspire and amaze," Downey Jr said of his son with actress/singer Deborah Falconer in a Facebook Post.
Indio's felony cocaine possession conviction was dismissed after he completed the rehab programme.
The actor also praised son's dedication towards his music. Indio is part of band The Dose, which released a new song 'Cold Hands' recently.
"I've also made it my business to be of as little help as possible, as nepotism usually does more harm than good... Just for today, I'm gonna ease up on that. Trust me and give these fine young men a listen," Downey Jr said.