The 45 year-old entered a facility following a string of alcohol related incidents that have occurred recently, reported Us Magazine.
"He realised he needed help and is committed to his sobriety," an insider said.
This announcement comes shortly after Brolin was caught in a drunken fistfight at O'Brien's Irish Pub in Santa Monica at the beginning of this month.
The report stated the fight occurred around 2am when the bouncers were closing the pub, but a drunken Brolin didn't want the night to end, the scuffle didn't last too long as both individuals were seen sharing a hug shortly after.
The actor was later reported saying that he was done with drinking and when asked if he regretted his recent antics the actor said, "Absolutely, it won't be happening again."
Brolin drinking heavily could have stemmed from his wife, Diane Lane, filing for divorce on February 15 of this year after 8 years of marriage. They have no children together and it was the second marriage for each of them. The divorce has yet been finalised.