"We can confirm that Robert Strauss passed away peacefully on March 19," the law firm he helped found, Akin Gump Strauss Hauer and Feld, said in a statement.
Strauss, born to Jewish German immigrants, died of natural causes at his home in Washington, the Dallas Morning News reported.
Considered one of Washington's master power brokers, the colorful Texas-born Strauss was known as "Mr. Democrat." But in an era when Washington was less polarized, Strauss easily crossed partisan lines and wielded influence in law, government and politics under a succession of presidential administrations.
"He is absolutely the most amazing politician," former first lady Barbara Bush wrote of Strauss. "He is everybody's friend and, if he chooses, could sell you the paper off your own wall."