Gray was attending tennis matches at Wimbledon with his youngest son, Andrew, a family spokesman said. No cause of death was available, The Philadelphia inquirer reported.
U.S. President Barack Obama released a statement Tuesday offering condolences and recalling Gray as a lawmaker who had wide-ranging impacts at home and abroad.
"Bill's extraordinary leadership, on issues from housing to transportation to supporting efforts that ended apartheid in South Africa, made our communities, our country and our world a more just place," Obama said. "Michelle and I extend our deepest sympathies to Bill's family, especially to his wife Andrea and their three sons."
Obama noted Gray was the first black lawmaker to serve as chairman of the House Budget Committee and as majority whip.
At the time of his death, Gray was chairman emeritus of Gray Global Advisors, a business and government consultancy based in Washington, the Inquirer said. Before he began the firm, he was president and chief executive officer of the United Negro College Fund. He also served as pastor for the Bright Hope Baptist Church in North Philadelphia.
Gray served in Congress from 1979 to 1991.
"He could walk down the hallway, and everybody knew him, he knew everyone," said U.S. Rep. Bob Brady, D-Pa. "I'm absolutely positively shocked. It's a major, major loss to the city, to the area and to the nation."