The actor, who entered rehab in 2013 for substance abuse - the same year he split from second wife Diane Lane - shared a lengthy post to Instagram on Monday, November 1, alongside a photo of himself shirtless and screaming.
In the caption, Josh thanked his spouse of nearly five years, Kathryn Boyd Brolin, mum to their two young daughters, 3-year-old Westlyn Reign, and 10-month-old Chapel Grace, and all of his children. He also has adult kids, Eden, 27, and Trevor, 33, from his first marriage to Alice Adair.
"Sobriety is climbing in your truck for a 6am call after 8 years of sobriety and there being a card from your wife telling you how grateful she is for having made the decision to put it down [sic]," the 53-year-old wrote.
"And sobriety is when your children look at you and trust what they see (you can see it in their pupils, and the way they stand before you) - that they know they are not being cultivated into some idea but celebrated for the original garden they are growing into."
He ended his post, "Sobriety is about living better than your remembrance of what your greatest drunk ever was - an everyday malleability into gratitude for what is. None of this is deserved. All of it is perception. Thank you God, family, and friends for the most punk rock sobriety imaginable. #deeplygrateful #westsidesobriety."