For a decade, Michael Cohen served as Donald Trump's lawyer and fixer, famously saying he would "take a bullet" for the president.
His job was simple: to clean up any problems the business man- turned-presidential candidate ran into.
From publicly boasting of his loyalty to the US president, Cohen co-operated with the investigation into possible Russian collusion in the 2016 election.
Having tied the last decade of his career personally to Mr Trump, it was an astonishing turnaround from the brash New Yorker.
Once front and centre of the Trump empire, Cohen would protect Mr Trump's image and business at all costs.
"If somebody does something Mr Trump doesn't like, I do everything in my power to resolve it to Mr Trump’s benefit,” Cohen told ABC News in 2011.
"I’m going to come at you, grab you by the neck, and I’m not going to let you go until I’m finished.”
....it means lying or making up stories. Sorry, I don’t see Michael doing that despite the horrible Witch Hunt and the dishonest media!
— Donald J. Trump (@realDonaldTrump) April 21, 2018
Behind the scenes, Cohen was fixing another problem for Mr Trump - buying the silence of two women who alleged affairs, porn star Stormy Daniels and former Playboy model Karen McDougal.
When the payments first came to light, Cohen was defiant and claimed they did not constitute campaign finance donations.
Cohen also praised Mr Trump's son, Don Jnr, for being "open, honest and transparent" over his handling of a controversial Trump Tower meeting with a Russian lawyer.
We know now that he had lied about the pretext for the meeting - first claiming it was to discuss Russian adoption and later admitting he was promised "dirt" on Hillary Clinton.
Cohen, 51, grew up on Long Island and graduated from Western Michigan University’s Cooley Law School, ranked among America's worst law schools in several lists.
In 1994, he married Laura Shusterman, the daughter of a Ukrainian immigrant who was a big player in New York city's notoriously rough-and-tumble taxi business.
But it was his place within Mr Trump's inner circle that led him into the tangled web of the Russia investigation, headed up by special counsel Robert Mueller.
Cohen was wounded when Mr Trump opted not to give him a role in the White House, reportedly on the advice of his daughter Ivanka and her husband Jared Kushner.
Left on the wayside, Cohen made a business out of his personal contact in the Oval Office.
The real turning point came in April, when the FBI raided his home and offices and seized hundreds of items - on the back of information handed to them by Mr Mueller.
A row over who should cover his legal fees followed, leaving Cohen uncertain his loyalty would be more cost-efficient than turning on his former boss.
Cohen initially said he used his own money to pay the porn star and was not reimbursed. Mr Trump, who first denied knowing anything about the payment, has since conceded that Cohen was paid back.
But Cohen’s case became an embarrassment and a threat to Mr Trump. The president declared early on that the investigation was all about Cohen’s private business, with nothing to do with him.
In a complete change in rhetoric, Cohen told the press his "first loyalty" was to his family and country - not Mr Trump. Faced with a lengthy stretch in prison, Cohen has now pointed the blame squarely at his former boss.
He testified in court that Mr Trump "directed him" to commit a crime by making payments to two women - with the express intention of influencing the election.
His lawyer, Lanny Davis, said a key factor in Cohen's decision to turn on the president had been Mr Trump's press conference in Helsinki with Vladimir Putin.
He said: "I can tell you that Helsinki was a significant turning point as he (Cohen) worried about the future of our country,"
Mr Davis said Cohen had been alarmed when he saw the president "aligning" with Mr Putin and "that shook up Mr Cohen".
He added: "From taking a bullet for Donald Trump, in the statement that he made, to seriously worrying about his unsuitability as president after he became president...it was an evolutionary process, a painful process."
Trusted with Mr Trump's most sensitive issues for 12 years, Cohen went on to be an invaluable witness for Mr Mueller's team.
Mr Mueller said Cohen had gone to "significant lengths to assist the Special Counsel’s investigation".