Phelps was arrested on Sept. 30 outside the Fort McHenry Tunnel, when he was stopped for speeding and crossing the double yellow line. Police said he was going 84 miles per hour in a 45 miles per hour zone, and registered a 0.14 percent on a blood-alcohol test. The legal limit in Maryland is 0.08.
"I now have the tools to move past this," Phelps told the judge Friday in court, according to the AP
. "What I did was wrong, and I made a bad mistake. I'm looking forward to having a much brighter future than I had in the past."
Phelps' attorney, Steven Allen, said he already attended a 45-day treatment program in Arizona, and that he will also participate in Alcoholics Anonymous.
In police footage ET obtained from the incident, the 29-year-old swimming superstar is seen getting handcuffed, and at one point, grins at a police officer while flashing his famous abs.
According to the Maryland Transportation Authority, Phelps was unable to "secure a ride home" after his arrest, so an MDTA police officer drove him back to his home.
Phelps' September arrest is the second time he's been arrested for driving under the influence. His first DUI arrest was in 2004 in Maryland, when he was 19 years old. He pleaded guilty in exchange for 18 months probation.