The Las Vegas Sun reports the 50-year-old rocker got out of the Clark County Detention Center Friday.
Neil pleaded guilty in January to driving drunk last summer near the Las Vegas Strip. He was sentenced to 15 days in jail and 15 days on house arrest under a plea deal that spared him a trial. He was also fined $585.
Neil could have faced up to six months in jail if convicted.
Las Vegas police said he was stopped in his black Lamborghini sports car June 27 after leaving the Las Vegas Hilton resort.
The jail and police didn't immediately return calls from The Associated Press.