"I'm sorry," Radel said at the start of a press conference in Cape Coral, Fla. "I've let down our country, I've let down our constituents, I've let down my family."
Radel, who in late October was caught buying cocaine from an undercover police officer, said that during his leave of absence, he would donate his salary to charity.
"I will be going in to treatment," Radel said. "And I am going to start with intensive in-patient treatment ... I have already begun the process."
Radel did not specify exactly what kind of treatment he would receive, referring instead only to a "disease." In a statement issued earlier on Wednesday, Radel disclosed that he struggled with "the disease of alcoholism." And during the press conference, he disclosed that his mother had been an alcoholic.
"I'm struggling with this disease, but I can overcome it," Radel said.
After entering his guilty plea in Washington, D.C. Superior Court on Wednesday, Radel was sentenced to one year of supervised probation and ordered to pay a $250 fine to a victims' compensation fund. If he successfully completes the probation, the court would then dismiss the case.
"I'm here tonight to take responsibility for what I did, to be held accountable for the bad decisions I made in my life," Radel said, adding that he wanted to become a "better man."