He founded the American Basketball Association, which revolutionized the game, and participated in other imaginative, sometimes zany sports ventures.Dennis Murphy, the impresario of alternative athletic leagues, including the American Basketball Association, who also shook up tennis and ice hockey and launched imaginative, sometimes quixotic ventures in other sports, among them indoor roller hockey, died on Thursday at an assistant living facility in Placentia, Calif. He was 94.His son, Dennis Jr., said the cause was congestive heart failure.Mr. Murphy’s most lasting achievement was the A.B.A., which he conceived, and which he started in 1967 as a cheeky competitor to the National Basketball Association. The league was known for its wide-open offenses; its red, white and blue ball; and the salary war it ignited against the N.B.A. to bring stars like Rick Barry and Zelmo Beaty into the upstart league.Mr. Murphy’s rationale for starting the A.B.A. was simple, as was his research into its viability: There were only 12 teams in the N.B.A.“There’s only one basketball league and one hockey league, so why not have another?” he was quoted as saying in Terry Pluto’s oral history “Loose Balls: The Short, Wild Life of the American Basketball Association” (1990). “Since I knew nothing about hockey, but basketball was my favorite sport, I figured I’d pursue the idea of a basketball league.”The A.B.A. thrived as a freewheeling hoops spectacle. It nurtured stars of its own, like Julius Erving and David Thompson, and generated excitement with the three-point shot and the All- Star Game slam-dunk contest, which eventually became staples in the N.B.A.“He wasn’t responsible for them, but he recognized their value and he went with it,” said Jim O’Brien, a reporter for The Sporting News who covered the Miami Floridians when Mr. Murphy was the team’s general manager. In an interview, he recalled Mr. Murphy’s promotional prowess and his willingness to make players accessible to the media.“He was fun and creative,” Mr. O’Brien said, “and he was always hustling somebody.”Mr. Murphy, center, at an A.B.A. meeting in Miami 1971. He was the general manager of the league’s Miami Floridians at the time.Arthur Hundhausen CollectionMr. Murphy had left the A.B.A. by 1972, four years before the league shut down and four of its teams — the New York Nets (who now play in Brooklyn), San Antonio Spurs, Denver Nuggets and Indiana Pacers — were absorbed into the N.B.A.Soon he was in the midst of itinerant league creation.He and Gary Davidson, another sports entrepreneur, in 1972 started the World Hockey Association, which challenged the dominance of the National Hockey League; in 1974, he and a group of partners, including the lawyer Larry King, who was then married to the tennis superstar Billie Jean King, formed World Team Tennis; and in 1976, he and Ms. King were among the founders of the International Women’s Professional Softball League.“He was a great cheerleader, a good manager and a skillful orchestrator at getting big egos to agree on things,” Mr. King said by phone.Of those three leagues, the W.H.A. probably had the greatest impact: It brought the Detroit Red Wings legend Gordie Howe out of a brief retirement to join the Houston Aeros, persuaded Bobby Hull to leave the Chicago Blackhawks for the Winnipeg Jets and signed the 17-year-old Wayne Gretzky to the Indianapolis Racers.Its level of play challenged the N.H.L.’s, just as the A.B.A.’s had challenged the N.B.A.’s. But its teams had financial difficulties, and the W.H.A. died in 1979. Four of its teams — the Edmonton Oilers, the New England Whalers, the Quebec Nordiques and the Jets — joined the N.H.L.“Murphy had a couple of things going for him,” the hockey writer Stan Fischler wrote recently in his column on Substack. “One was that N.H.L. president Clarence Campbell never took the W.H.A. seriously — until too late.”Another, Mr. Fischler said, was chutzpah. Before the W.H.A. started, Mr. Murphy showed up at a minor-league hockey meeting in the Bahamas, posing as a reporter, and started asking Emile Francis, the general manager of the New York Rangers, about the N.H.L.’s plans for expansion.Soon after, Mr. Francis was watching television and saw Mr. Murphy being interviewed by another reporter about the league he planned to start.Dennis Arthur Murphy was born on Sept. 4, 1926, in Shanghai, where his father, Arthur, was an engineer for Standard Oil. His mother, Adele (Gurevitz) Murphy, was a homemaker. The family moved to Brentwood, Calif., in 1940.After serving in the Army in the Philippines, Mr. Murphy attended the University of Southern California, where he earned a bachelor’s degree in economics.For most of the 1950s and the early ’60s, Mr. Murphy worked at an engineering firm. For two years during that period, he was the part-time mayor of Buena Park, in Orange County.His fascination with sports leagues continued with the creation in 1981 of Team Tennis, also with Mr. King, after World Team Tennis failed in 1978. Team Tennis would later adopt the name of its predecessor and rechristen itself World Team Tennis. And in the early 1990s, Mr. Murphy, Mr. King and Ralph Backstrom, a former N.H.L. player, formed Roller Hockey International, an attempt to capitalize on the popularity of in-line skating.“We believe we can be the No. 1 hockey sport,” Mr. Murphy told The New York Times in 1994.But the league played its last season in 1999, when the champion St. Louis Vipers won the Murphy Cup. One of his mistakes, Mr. Murphy told The Hockey News in 2019, had been expanding to 24 teams in the league’s second season.“We should have kept it smaller and then expanded,” he said. “But we did it for money. I had a lot of contacts through my other leagues. Everybody wanted to get in because of our success in the other leagues. So they put pressure on me, and I fell for it.”Besides his son, Mr. Murphy is survived by his daughters, Dawn Mee and Doreen Haarlamert; eight grandchildren; and seven great-grandchildren.The A.B.A. did not have a national television contract and struggled for attention. The Floridians, for example, had bikini-clad cheerleaders, an idea that came from a publicist.“The idea was that we needed to get attendance at the games,” Mr. Murphy told The Reno Dispatch, a blog, in 2013. The cheerleaders, he added, were always on the visitors’ side of the court “so the visiting players would look at girls rather than pay attention to the game.”Alex Traub contributed reporting. More