Michael Cohen sums up his extraordinary closeness with US President Donald Trump in one word: "Loyalty."
After setting up a committee in 2011 designed to boost the possibility of a Trump presidential bid, he described his role as "fixer" in this way: "It means that if somebody does something Mr Trump doesn't like, I do everything in my power to resolve it to Mr Trump's benefit. If you do something wrong, 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."
Loyalty, he has said, spurred him to regularly threaten lawsuits against those he perceived as threats to Trump. Loyalty, he said, prompted him to use a home equity line of credit to finance a payment of US$130,000 to adult-film star Stormy Daniels for her silence.
He even compared himself on Twitter to Ray Donovan, the fictional television character of the SoHo series on Sky who goes to whatever lengths necessary to fix problems for the moguls he serves.
Now, in the wake of yesterday's raid by federal agents on his law office, a looming question is whether Cohen went too far in seeking to solve Trump's problems.
The raid was aimed at seizing documents related to the Daniels payment. It was based on a referral to the US Attorney for the Southern District of New York from special counsel Robert Mueller, who is investigating whether the Trump campaign colluded with Russia.
"This is a very, very unique relationship, one that was remarkable," said Michael Caputo, a former Trump political adviser. "I've never seen someone so loyal to their boss . . . . You don't get that close to the President without being someone he trusts implicitly. I can't imagine Michael Cohen endangering the President under any circumstance under the sun."
Cohen, 51, grew up on Long Island, became a lawyer, served as an intern to a Democratic congressman and went into the New York City taxi business.
He simultaneously ran a law office, which defended his taxi interests. His business thrived, but subsequent efforts to enter politics failed with unsuccessful bids for New York City Council and state senate. Some of his business ventures floundered, including a casino boat based in Florida. His wife, Laura, is a native of Ukraine, and Cohen has said he speaks rudimentary Russian.
By 2001, Cohen, who said he had admired Trump for years, bought his first property in a Trump building and encouraged family members to do the same. Around 2006, after Trump got to know Cohen through his condo purchases - as well as an introduction from Donald Trump jnr - Cohen became executive vice-president and special counsel of the Trump Organisation. "Michael Cohen has great insight into the real estate market," Trump told the New York Post in 2007, referring to Cohen's purchases of condo in his buildings.
Cohen was an early supporter of Trump's presidential ambitions, creating the 2011 committee called "Should Trump Run?" and flying to the first-caucus state of Iowa to explore the possibility. "Are you one of the many frustrated Americans sick and tired of hearing the same old mundane political campaign promises?" the website asked. " . . . We need to convince Donald Trump to run for President in 2012."
The Federal Election Commission, which enforces the laws limiting campaign donations, dismissed a complaint that Cohen delivered an "in-kind" contribution to Trump through such work. After Trump did not run in 2012, Cohen talked regularly with Trump about running in 2016 and became one of his most public defenders.
"Michael Cohen was in every single meeting I attended before the campaign," Caputo said.
It was mostly left to others to defend Trump in court. Cohen's job was to reprise the role once played by one of the most important men in Trump's life: lawyer Roy Cohn, the pugnacious lawyer who taught Trump that the best way to survive was to counterpunch 100 times harder.
When a reporter for the Daily Beast in 2015 quoted a deposition from Trump's first wife, Ivana, who said she had been "raped" by Trump, Cohen told the reporter, as reported by the website: "You write a story that has Mr Trump's name in it, with the word 'rape,' and I'm going to mess your life up . . . for as long as you're on this frickin' planet . . . you're going to have judgments against you, so much money, you'll never know how to get out from underneath it." Ivana Trump later said, "I referred to this as a 'rape,' but I do not want my words to be interpreted in a literal or criminal sense."
The Daily Beast published the story, prompting Trump's campaign to say Cohen "is not affiliated with the campaign." Cohen later apologised for saying that a spouse cannot be raped.
A number of journalists have said Cohen threatened them with libel suits.
After Buzzfeed last year published the contents of the Russian "dossier," Cohen in January sued the publication and a consulting firm, Fusion GPS, that produced it because the document alleged that he met with a Russian official in Prague, among claims about possible collusion between Russia and the campaign. "Enough is enough ... just filed a defamation action," Cohen tweeted. Cohen denied that such a meeting took place.
Cohen's finances are not public, and it is not known how much he was paid by Trump, whose company is privately held.
Cohen did his own savvy real estate ventures. He bought a building for US$2 million at 172 Rivington Street in New York City in 2011 and sold it for US$10 million three years later, according to property records. He sold several properties in 2015 and used the proceeds to help purchase a US$58 million building for a condo conversation, according to the Real Deal.
He was Trump's liaison on a number of deals around the world, including in the former Soviet republics of Georgia and Kazakhstan.
Early last year, Cohen went beyond his usual role and received the delivery of a peace plan between Russia and Ukraine in a way that could have enabled Trump to lift sanctions on Russia. Cohen has said he threw away the plan, given to him by a former Trump business partner.
Cohen, meanwhile, was busy handling a number of potential threats to Trump. Karen McDougal, a former Playboy playmate who said she had an affair with Trump in 2006, said she sold her story to the National Enquirer, which did not publish it. McDougal said in a lawsuit that the Enquirer's parent company, American Media "worked secretly with Mr Trump's personal 'fixer,' - Cohen - to suppress her story.
However, the payment to Stormy Daniels thrust Cohen into the full glare of scrutiny.
Daniels, whose real name is Stephanie Clifford, has said she also had a sexual relationship with Trump in 2006. Trump has denied it. Daniels told her story in 2011 to In Touch magazine, but several of those who worked at the publication have said they withheld the story after Cohen threatened to sue.
Last week, asked if he was aware that Cohen had paid US$130,000 to Daniels, Trump said he did not know about it. "You'll have to ask Michael Cohen," Trump said. Cohen did not make a public statement in response to Trump's comment. Instead, he tweeted, "A person who deserves my loyalty receives it." Using the acronym for President of the United States," he said: "I will always protect our @POTUS."