Cohen says hush money was paid over Trump election concerns
Donald Trump's former personal lawyer says he bought the silence of two women because Mr Trump was "very concerned" about how their stories of alleged affairs with him would affect his election chances.
In an interview with ABC News, Michael Cohen said he "gave loyalty to someone who, truthfully, does not deserve loyalty".
Cohen was sentenced on Wednesday to three years in federal prison. He pleaded guilty to several charges, including campaign finance violations and lying to Congress.
Prosecutors have said the president directed him to arrange the payments to buy the silence of porn actress Stormy Daniels and former Playboy model Karen McDougal in the run-up to the 2016 campaign.
Cohen says he is angry with himself for the deals.
Mr Trump has denied directing Cohen to break the law.
Mr Trump's former "fixer" said: "I am done with the lying. I am done being loyal to President Trump.
"I will not be the villain of this story."
Asked whether the president knew it was wrong to make the payments, Cohen said: "Of course," but he did not provide any specific evidence or detail in the interview.
The president has asserted in a barrage of tweets over the last few weeks that Cohen is a "liar" who cut a deal to get a reduced prison sentence.
But Cohen said Mr Trump "directed me to make the payments, he directed me to become involved in these matters".
He added: "He knows the truth. I know the truth. Others know the truth. And here is the truth: People of the United States of America, people of the world, don't believe what he is saying. The man doesn't tell the truth. And it is sad that I should take responsibility for his dirty deeds."
In a separate case, Cohen pleaded guilty to lying to Congress about his work on a possible Trump real estate project in Moscow and said he did so to be consistent with the president's "political messaging".
The charges in that case were brought by special counsel Robert Mueller's office and Mr Mueller's prosecutors have said Cohen has provided key information in their investigation.
Cohen has said he is continuing to co-operate with investigators.