That a person with Schiller's profile is now a senior White House aide with near round-the-clock access to the president is just one more way in which the Trump White House has broken with norms set by previous administrations.
"The president has exceptional confidence in Keith. If he asks him to do something, he knows it will get done," said Corey Lewandowski, Trump's former campaign manager who worked closely with him.
Schiller has long been critical of Comey, telling those around him that the FBI was not aggressive enough in its investigation of Hillary Clinton's use of a private email server and his views helped shape those of his boss, according to a person close to Trump who requested anonymity in order to talk about internal deliberations. Schiller remains in touch with many law enforcement officers and has often served as Trump's liaison with police departments.
He has also repeatedly gotten physical on Trump's behalf, punching a protester outside of Trump Tower, forcibly removing a reporter from a press conference and confronting many who interrupted Trump's rallies.
In a young White House that is considered one of the leakiest in history, Schiller has become one of the few people that the president can talk with and know that their conversation will not be repeated to others. White House officials often look to Schiller for tips on the president's mood or how best to approach him.
"Keith Schiller is not just some bodyguard," said Michael Caputo, a political adviser who worked with Trump between 2013 and 2016. "Nobody knows the score among the advisers better than Keith Schiller. . . Keith's always known what's what among the people who are in Donald Trump's orbit."
When Trump's son-in-law Jared Kushner traveled to Iraq in April, Schiller came along - getting a seat at the table during talks with the Iraqi government, standing in group photos and hovering in background of photos of Kushner. Iraqi specialists in the government who typically would participate in such trips were not included, being told there wasn't enough room for them on the plane.
Schiller turns down most interview requests - including one for this story - although he agreed to be interviewed on New Year's Eve 2015 at Trump Tower by Rich Siegel, a high school friend. The 55-minute conversation was posted on Facebook and provides a rare narrative of Schiller's years-long relationship with Trump.
After seeing Maples' bodyguard at the Manhattan District Attorney's Office, Schiller reached out to Trump and started working for him part-time in 1999. In 2004, following his retirement from the police department, Schiller became the Trump Organization's director of security. Schiller followed Trump onto the campaign trail, providing security in the months before the Secret Service took over - and then continuing to provide an added layer of protection, not hesitating to keep reporters away from the candidate or venture into rally crowds to confront protesters, sometimes physically.
Some who have worked with Schiller gushed as they described him, painting a softer portrait than the image of the imposing 6-foot-4-inch bodyguard with closed-cropped hair and an often stern demeanor.
Eric Trump, one of the president's sons who worked with Schiller for years at the Trump Organization, described the bodyguard as someone who has "always demonstrated incredible work ethic and loyalty." Lewandowski described Schiller as "the guy you want next to you in the foxhole when things go badly."
In the 2015 conversation with his high school friend, Schiller explained that his pre-Trump years prepared him for a career that has taken him into exclusive night clubs, skyboxes at sporting events, business meetings overseas and all over the United States as Trump campaigned for president.
David Chong, who served as Schiller's boss for eight years on a New York City Police Department task force on high intensity drug trafficking areas, said Schiller "loved the aura of being a New York City detective that was attacking the biggest and baddest drug cartels."
Schiller - who grew up in New Paltz, N.Y., and is married with two children - was known among his fellow police officers for his size and strength, Chong recalled. When his unit would raid apartments up many flights of stairs, Schiller would volunteer to carry the 60-pound battering ram. At the top of the stairs, instead of handing it off to men with fresh arms to break through the door, Schiller would slam the ram himself.
"He was strong as an ox," said Chong, who now serves as the public safety commissioner in White Plains, N.Y., adding that above all Schiller was known for "extreme loyalty to his boss."
When Schiller went to work for Trump, he was given a Trump Tower office on the same floor as the celebrity and at times spent as much of 90 percent of his time in Trump's presence.
In 2007, Schiller briefly stepped into the spotlight, as his boss took part in a staged WWE event with the wrestling organization's chief, Vince McMahon. As part of the act, Trump slapped McMahon, who acted stunned and then began to charge at Trump - only to be stopped by Schiller, who stepped forward to block McMahon, pushing the wrestling executive repeatedly backward before throwing him to the ground.
In one incident in September 2015, Schiller grabbed a sign from a protester outside Trump Tower. As Schiller marched back toward the building holding the sign, the man rushed at his back. Schiller whirled - and punched the man in the face.
Protester Efrain Galicia and other demonstrators from that day are now suing Schiller and Trump over the incident. Schiller testified in a sworn deposition in December that he believe Galicia's sign was creating a safety hazard by impeding access to the sidewalk and that he punched him in self-defense, believing the protester was reaching for a gun hidden under his suit jacket.
Schiller acknowledged in the testimony that at the time of the incident, he did not hold a valid New York state security guard license. He said he had allowed his license to lapse, believing that a different federal license that allowed him to carry a gun on private airplanes was sufficient.
In another incident a few days earlier, in August 2015, Schiller removed Univision anchor Jorge Ramos from a Trump campaign press conference after Ramos repeatedly questioned Trump about immigration.
"Sit down! You haven't been called. Go back to Univision," Trump told Ramos, as the reporter continued to press. Then, video of the incident shows that the presidential candidate turned to his left, appearing to lock his gaze at something in his field of vision.
Schiller then immediately appeared, crossing behind Trump and approaching Ramos, quickly grabbing Ramos's shoulder with one hand and placing the other on the reporter's chest before pushing him backwards towards the exit, the video shows.
Asked in his December deposition if he had put his hands on Ramos, Schiller responded, "No, I don't believe so."
In the New Years Eve conversation with Siegel, Schiller spoke about some of the most difficult moments in his life: the death of his mother when he was 17 and being in Manhattan on Sept. 11, events that he recounted emotionally.
Asked if he ever has these sorts of conversations with Trump, Schiller replied: "It's a business relationship."
