Norman Dorsen, a passionate human rights advocate who led the American Civil Liberties Union for 15 years and was involved in some of the biggest civil liberties cases of the second half of the 20th century, died on Saturday at his home in Manhattan. He was 86.

The cause was complications of a stroke, his daughter Annie said.

Mr. Dorsen’s career-long focus on civil liberties was informed by his involvement in the Army-McCarthy Hearings in 1954. He went on to argue Supreme Court cases that established juveniles’ rights to due process and that acknowledged the rights of children born out of wedlock. He was also one of the first lawyers to argue before the court in favor of abortion rights and gay rights.

Mr. Dorsen was a key figure at New York University School of Law, where he joined the faculty and became the director of the civil liberties program in 1961. Partly through Mr. Dorsen’s influence, the school gained a reputation for attracting students and faculty with an interest in public interest law.

“Perhaps no one else in the history of N.Y.U. Law shaped this place as profoundly, or affected it as deeply, as Norman,” said Trevor W. Morrison, the school’s dean.