Marvin Miller, the union leader who created free agency for baseball players and revolutionized professional sports with multimillion dollar contracts, died Tuesday. He was 95.

Miller died at his home in Manhattan at 5:30 a.m., said his daughter Susan Miller. He had been diagnosed with liver cancer in August.

In his 16 years as executive director of the Major League Players Association, starting in 1966, Miller fought owners on many fronts, winning free agency for the players in December 1975. He may best be remembered, however, as the man who made the word “strike” stand for something other than a pitched ball.

Miller, who retired and became a consultant to the union in 1982, led the first walkout in the game’s history 10 years earlier. On April 5, 1972, signs posted at major league parks simply said “No Game Today.” The strike, lasted 13 days.

Miller’s ascension to the top echelon among sports labor leaders was by no means free from controversy among those he would represent. Players from the Los Angeles Dodgers, Atlanta Braves, California Angels and San Francisco Giants opposed his appointment as successor to Milwaukee Circuit Court Judge Robert Cannon, who had counseled them on a part-time, but unpaid basis.