The police said that staff members at the Casablanca Hotel, on West 145th Street, discovered Meminger unconscious in his room and that emergency medical personnel pronounced him dead. The cause was under investigation, but the police said there were no signs of trauma.

Meminger had long battled an addiction to cocaine and had acknowledged using drugs as far back as his N.B.A. days, when he was among a glamorous cast of Knicks in the franchise’s glory years. In 2009, he was critically injured in a four-alarm fire in his room in a building in the Bronx.

“They call him Dean the Dream, and he is all of that and more,” Coach Lou Carnesecca said after his St. John’s team was beaten by the Marquette squad led by Meminger in the final of the 1970 National Invitation Tournament at Madison Square Garden. Carnesecca had followed Meminger since he was recruited by Rice High School of Manhattan out of a grammar school basketball tournament.

Al McGuire, Meminger’s coach at Marquette, once said he was “quicker than 11:15 Mass at a seaside resort.”

Meminger, the Knicks’ first-round pick in the 1971 N.B.A. draft, joined a brilliant backcourt led by Walt Frazier, Dick Barnett and Earl Monroe. At 6 feet 1 inch and 175 pounds, he may have seemed overmatched, and he was often a backup. But he was a whirlwind dribbling upcourt, a superb defensive player and a clever ball handler with fine court sense.

His most memorable moments came in Game 7 of the 1973 Eastern Conference finals, when he replaced Monroe in the second quarter, frustrated the hot-shooting Boston Celtics guard Jo Jo White and scored 13 points. After knocking the Celtics out of the playoffs, the Knicks beat the Los Angeles Lakers for the title.

“Dean went out and shut Jo Jo down, and we won that game,” said Phil Jackson, the former Knicks forward and Bulls and Lakers coach. “It was a signature performance in our history.”

Meminger joined other members of the 1973 Knicks team for a ceremony at the Garden on April 5. “There was no one prouder than Dean to be back on the court with his teammates,” Glen Grunwald, the Knicks’ general manager, said in a statement. 

A native of Walterboro, S.C., Meminger came to Harlem with his family as a seventh-grader, then starred at Rice and became a dazzling figure at West 135th Street playground games.

“By the time I was 18, I was considered a ballplayer by the other dudes in the park,” he once said. “They were 23, 27, 35 years old, but I could participate. It’s very rugged out here. It’s more physical than the N.B.A.”

Meminger became an all-American guard at Marquette, averaging 18.8 points for three seasons, and was named the most valuable player of the 1970 N.I.T. After three seasons with the Knicks, he played for two with the Atlanta Hawks, then returned to the Knicks in the 1976-77 season. He had a career average of 6.1 points a game.

Meminger coached the New York Stars to the Women’s Professional Basketball League championship in 1980. Two years later he was named coach of the Albany Patroons of the Continental Basketball Association, but Jackson replaced him in midseason.

He was long plagued by drugs. In an interview with The New York Times in 2003, when he was coaching at Manhattanville College in Purchase, N.Y., Meminger said his cocaine use had escalated after he left the N.B.A. He said he had received treatment for addiction but had several relapses, even while working as a drug counselor. But he said he had been drug free since June 2001.

“Once I left basketball I used to medicate that pain, ache, emptiness â€" at least that was my perception,” he said. “I isolated my family, alienated my kids.”

He told of fathering children with his high school and college sweethearts and said he had not helped raise his son, Dean Jr., a reporter for the cable television station NY1, or his daughter, Maisha Meminger, who received a graduate degree in social work.

“If I wanted to say somebody was my son, Dean is my son,” he said. “Understands what values are, a loyal, family guy. I don’t know where he learned it from.”

J. David Goodman, Ravi Somaiya and Harvey Araton contributed reporting.