"I couldn't believe the level of courage I was witnessing," the "West Wing" star said at an event in Florida.
"I hope that this day is the first day of the rest of Charlie's life as a free man," addded the 75-year-old actor.
Charlie Sheen ended days of intense media speculation by confirming he is HIV positive in a NBC TV interview.
"I have to put a stop to this onslaught, this barrage of attacks and of sub-truths," Sheen told Today show host Matt Lauer, adding he was diagnosed four years ago.