Nearly three decades ago, John Gleeson made his name by successfully prosecuting the man known as "
The Teflon Don."
Now he finds himself mixed up in a case tied to the modern-day inheritor of that nickname.
On Wednesday, Gleeson became the latest participant in the turbulent criminal case against President Donald Trump's former national security adviser
Michael Flynn
, after the federal judge overseeing the case appointed Gleeson to oppose the Justice Department's effort to drop it.
The Field of Fight: How We Can Win the Global War Against Radical Islam and Its Allies by Michael Flynn.
An esteemed former federal judge himself, Gleeson, 66, entered the discourse around the Flynn case on Monday, when he and two other former Justice Department officials wrote in The Washington Post that among the steps US District Judge Emmet Sullivan could take would be to "appoint an independent attorney to act as a 'friend of the court,' ensuring a full, adversarial inquiry."
Saying the case "reeks of improper political influence," they wrote that "if prosecutors attempt to dismiss a well-founded prosecution for impermissible or corrupt reasons, the people would be ill-served if a court blindly approved their dismissal request. The independence of the court protects us all when executive-branch decisions smack of impropriety; it also protects the judiciary itself from becoming a party to corruption."
Now, according to Sullivan's order, Gleeson will articulate an argument against the Department of Justice's effort to end the prosecution and will weigh whether Flynn should face a perjury charge for contradictory statements he has given the court.
Former colleagues, contemporaries and friends of Gleeson's -- even some who have expressed sympathy for Flynn's position -- said they expect Gleeson's rigor, intellect and experience to be a welcome counterweight to the tumult of the case so far. Through a spokesman at the law firm where he is a partner, Debevoise & Plimpton, Gleeson declined to comment for this story.
Known for his boyish looks, penchant for cardigans and sweater vests, and habit of eating tuna fish straight from a can for lunch even as a judge, Gleeson rose to prominence as a federal prosecutor in the Brooklyn US attorney's office in the early 1990s, when he won a murder and racketeering trial against Gambino crime boss John Gotti, known as "The Teflon Don."
"I have never been exposed to someone as prepared, as fair, as impartial, as unbiased and as precise in his language as John Gleeson," said James Gagliano, a retired FBI agent and a CNN law enforcement analyst who worked as an agent on the Gotti case when it went to trial. "John could spell a death knell for a case just in three or four words."
Gagliano was 26 years old when he was assigned to the Gotti case, but "John never treated me like a junior agent. He treated me as an equal and as a contemporary."
Though Gagliano has said he believes Flynn has been mistreated by law enforcement, he said: "When it comes to John Gleeson, there is no one that is going to question his credentials."
In the Brooklyn prosecutors' office, Gleeson served as chief of its organized crime section and chief of its criminal division, during which time he became close with a colleague, Andrew Weissmann, who would go on to become a top prosecutor in special counsel Robert Mueller's office. Gleeson and Weissmann remain friends, according to a person who knows the men. Weissmann declined to comment.
In 1994, at the age of 41, Gleeson became one of the youngest federal judges after being nominated by President Bill Clinton. When Gleeson first arrived on the bench, some of his former colleagues from the Brooklyn US attorney's office anticipated he might be lenient when sentencing their cooperating witnesses.
Just before his appointment, Gleeson had won an extraordinary prison term for Salvatore Gravano
, the Brooklyn mobster also known as "
Sammy the Bull," who had been a star witness in the Gotti case. Gravano, who admitted in testimony to participating in 19 murders, was sentenced to five years after Gleeson argued he had "rendered extraordinary, unprecedented, historic assistance to the government."
Underboss: Sammy the Bull Gravano's Story of Life in the Mafia.
In his new role, however, Gleeson was no more forgiving than his black-robed colleagues. "He wasn't influenced by the fact that as a prosecutor he advocated for leniency for important cooperators. He realized that as a judge he would have to be neutral and form a fact-based and precedent-based view," said Jodi Avergun, a white-collar defense attorney at the law firm Cadwalader, Wickersham and Taft who worked with and later tried cases before Gleeson.
Later in his career, Gleeson would go on to speak out about what he described as the "excessive severity" of the federal criminal justice system, and he became an advocate for alternatives to incarceration. "I didn't fully appreciate this in my early days as a judge," he told the Wall Street Journal in 2016. "I'd spent 10 years bringing to justice gangsters -- most of them for murders," Gleeson said. "They were part of the narrow slice of the caseload that actually deserved the severity our system visited on them. It took me a while to fully appreciate how wrong and unfair it was to spread that harshness across the entire caseload, including low-level, nonviolent defendants."
Others who appeared before Gleeson recalled the austerity of his courtroom practices. "You wear white shirts on Gleeson days," said a former federal prosecutor who appeared before Gleeson numerous times. "He thought prosecutors should wear a white shirt and a striped tie in his courtroom. You would find out in an embarrassing way," the former prosecutor recalled. "He would ask, 'Is that a blue shirt you're wearing?' "
Gleeson, this person recalled, held prosecutors "to a standard that was super high in every way."
The son of Irish immigrants, Gleeson found performing naturalization ceremonies to be one of his favorite parts of being a judge, recalled Mimi Rocah, a Democratic candidate for district attorney in Westchester County, New York, and a former prosecutor who worked as a judicial clerk for Gleeson. "He really took very seriously and to heart this idea of where his family came from and a very patriotic view of America as a fulfillment of the American dream that he could become a judge," she recalled.
Gleeson's 22 years on the bench were marked by some controversies, including one case that was publicly criticized, in which he approved a deferred prosecution agreement between the Department of Justice and the bank HSBC to settle allegations that HSBC processed payments for Mexican drug cartels. As part of the settlement, the bank paid $1.2 billion and agreed to the appointment of an independent monitor who was required to write a confidential report as to whether the bank had taken steps to improve its compliance program.
In that opinion, Gleeson commented on the power of prosecutors and the court to determine the course of a prosecution, a topic relevant to what happens next in the Flynn case. Gleeson wrote that "the government has absolute discretion to decide not to prosecute," but added that "a pending federal criminal case is not window dressing. Nor is the Court, to borrow a famous phrase, a potted plant."
Despite taking heat at the outset, Gleeson later, against the wishes of the bank and the Justice Department, ruled that the monitor's confidential report should be made public, citing the public's right to access. "My oversight of the DPA and the open criminal case goes to the heart of the public's right of access: federal courts must 'have a measure of accountability,' and the public must have 'confidence in the administration of justice,' " the judge wrote in an opinion. (An appeals court later reversed the decision.)
Rocah said Gleeson has a history of doing what he believes is the right thing, even if it hasn't been done before, a trait she believes makes him the right person for the Flynn case. "He's one of these people that's very guided by principle and what he thinks is the right thing to do, which I think is important here," Rocah said. "He really is a judge who is very concerned about looking out for the rights of defendants. Flynn is a defendant and a person with rights," she said. "It's going to be really hard for anyone to paint Gleeson as some hard-charging, 'lock him up and throw away the key' person. That is absolutely not who he is."
Thanks to
Erica Orden, Kara Scannell and David Shortell.
in 1986, an informant told the FBI, according to testimony in October of 2007, in Brooklyn state court. But while the late Gambino crime boss 
