Story highlights Schiller hand-delivered a letter from the President firing FBI director James Comey

He joined the Trump Organization as a part-time bodyguard in 1999

Washington (CNN) Few people inside Donald Trump's orbit are more important than Keith Schiller, the President's longtime bodyguard who has risen from part-time hired muscle to director of Oval Office operations.

That status was cemented on Tuesday when the former New York Police Department officer hand-delivered a letter from the President firing FBI director James Comey, entering the FBI headquarters with a manila folder and leaving without it.

Schiller, a White House official told CNN, went to the headquarters expressly to fire Comey, even though the FBI is currently in the middle of an investigation into Russia's meddling in the 2016 election and ties the hackers may have had to Trump associates.

Schiller is widely regarded inside and outside the White House as the "most underestimated person on Trump's team," as one former aide put it -- someone with constant access to Trump who has not only developed a deep level of trust with the President, but also has turned into a sort-of Trump translator.

During the campaign, "it mattered more to me what Keith Schiller thought of me than what the campaign manager thought," a former top campaign aide told CNN about Schiller. "Now I think it means more what Keith thinks of you than Reince (Trump's chief of staff) thinks of you."

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