For President Clinton, he has also been a frequent back-channel trouble- shooter. This time, though, it seems as if he himself is implicated in the trouble.
From his suite in the Washington law firm of Akin, Gump, Strauss, Hauer & Feld, Mr Jordan, 62, has arguably wielded more power during this administration than many in the White House itself.
It is a role that began when he headed President Clinton's transition team after his election in 1992.
Mr Jordan first came to prominence in the Sixties as a leading voice in the civil rights movement.
He has experience of crises. In 1980 he survived an assassination attempt when he was fired at by a racist gunman in a motel parking lot in Fort Wayne, Indiana.
Mr Jordan's manoeuvrings on the President's behalf came under scrutiny when the special Whitewater prosecutor, Kenneth Starr, discovered that he had helped another Clinton buddy, Webster Hubbel, get a new job after Mr Hubbel had pleaded guilty to mail fraud dating back to his lawyer days in Little Rock.
Mr Jordan did once formally represent the President on an official visit to Taiwan.
Otherwise, he is more familiar as one of Mr Clinton's best golfing friends and the person the President turns to always in times of calamity.
"The President needs to go somewhere he can relax," Mr Jordan once remarked. "We talk like men. There's nothing wrong with a little locker-room talk. He knows I'm up late at night, I get up early, I'm always available for advice."
The President once hauled Mr Vernon from the 11th tee during a celebrity golf game because he had a question to put to him.
The suspicion now is that Mr Jordan called on his friend and Democratic contributor Ronald Perelman to find Monica Lewinsky safe haven in the public-affairs office of one of the companies he controls, Revlon cosmetics.
That such a job was offered has now been confirmed.
And Revlon happens to be one of about 11 corporations on which Mr Jordan has a seat on the board.
If it is proved that the job offer was designed to buy silence from Ms Lewinsky, the big man who glides around Washington in a red convertible Cadillac and attends all the best parties may not be able to save even himself.