But he said he was braced for a barrage of lawsuits, given that in 35 states, infecting someone with HIV is a criminal offence.
The father of five, whose breakdown in 2011 and bizarre episodes caused headlines around the world, said he felt he could no longer keep his condition secret.
His three ex-wives, including Denise Richards, a Bond girl, and actress Brooke Mueller, have known about his condition for a while, and they and their children have all tested negative for the virus.
Sheen told the programme: "I have to put a stop to this onslaught, this barrage of attacks and of sub-truths and very harmful and mercurial stories that are about me, that threaten the health of so many others that couldn't be further from the truth.
"I have a responsibility now to better myself and to help a lot of other people ..."
A prostitute who found his medication in the bathroom was among the numerous people to blackmail him, he said. Asked if he was still paying her, the Platoon actor said: "Not after today I'm not."
He said he had struggled with the diagnosis, which he initially thought was a brain tumour. Since his breakdown he has admitted to sleeping with more than 5000 women including porn stars, prostitutes, groupies and strippers.
"It's a hard three letters to absorb," he said of his condition.
HIV is no longer the death sentence it once was, and modern treatments can mean that a sufferer lives a normal life for many years. Sheen, born Carlos Estevez, whose father Martin starred in The West Wing and whose brother Emilio Estevez is also an actor, said he didn't know how he contracted the virus.
He is taking four pills a day, he said, and his doctor confirmed that he has a low viral load [the amount of HIV in a blood sample] and does not have Aids.
But Sheen, who has sought treatment for drug and alcohol addiction many times, admitted he was still drinking.