Miller, Marvinin full Marvin Julian Miller  ( born April 14, 1917 , Bronx, New York, U.S.—died November 27, 2012 , New York City )  American union leader who drove successful efforts, as head of the Major League Baseball (MLB) Players Association, to improve ballplayers’ labour rights, revolutionizing the business of professional sports as a result.

Miller graduated from New York University (1938) with an economics degree. After being employed as an economist by the U.S. government during World War II, he began working with labour unions, and in 1950 he took a position with the United Steelworkers Union, eventually becoming its principal economic adviser. In 1966 the 12-year-old MLB Players Association, seeking to establish itself as a formal union to better address players’ grievances, hired Miller as its executive director. Within the first five years of his leadership, the union negotiated a significant raise to the MLB minimum wage, a generous player pension system, a first-ever collective-bargaining agreement, and the right for players to have their disputes with management arbitrated.

Miller’s most notable accomplishment was overturning the long-standing reserve clause in players’ contracts, which effectively bound them to the teams that originally signed them for as long as the teams desired. Although a legal challenge backed by Miller was rejected by the U.S. Supreme Court in 1972, three years later the MLB arbitrator invalidated the prevailing interpretation of the clause, ruling that it allowed only for a single one-year contract extension. The decision opened the door to free agency, by which players whose contracts had expired could sell their services to the highest bidder. The impact of the advent of free agency on the history of professional sports cannot be overstated: it permanently changed the nature of management-player relations from an unquestioned quasi-feudal association to something approaching an equal partnership. While not on par with the most historic landmarks of the labour movement, the creation of free agency on such a public stage and with a generally admired workforce was nevertheless one of the most significant victories for workers in the second half of the 20th century. Miller’s legacy in the sporting world also includes the advent of organized player strikes, several of which he oversaw before he retired in 1982.

Despite his historic impact on baseball, Miller was repeatedly passed over for induction into the Baseball Hall of Fame in the years after his retirement. He did not appear on any veterans committee ballot between 1982 and 2001, and he was rejected in 2003, 2005, 2007, and 2009 numerous times thereafter by selection committees with significant ownership presences.