Joseph S. Iseman, a New York lawyer and educator who worked with Vladimir Nabokov, Robert Motherwell, National Educational Television and Bennington College, where he memorably stepped in as acting president in 1975, died on Tuesday at his home on the Upper East Side of Manhattan. He was 89.

The cause was cardiac arrest, his family said.

Mr. Iseman was associated for 64 years with the firm of Paul, Weiss, Rifkind, Wharton & Garrison, since 1954 as a partner and then senior partner. In 1987, he became of counsel for the firm in Paris and New York. He specialized in private international and probate law, including wills and trusts.

Joseph Seeman Iseman was born in Manhattan and attended the Ethical Culture School. He graduated magna cum laude from Harvard in 1937 and received his law degree at Yale in 1941.

During World War II he was a captain in the Air Transport Command, stationed in Abadan, Iran. On behalf of the United States government and in collaboration with Trans World Airlines, he then assisted the Iranians in organizing a national airline. He bought up surplus DC-3's in Cairo and flew them to Tehran, where he learned Farsi and became the first operations manager of the new Iranian Airways. He described his experiences in a memoir, "Nine Months on a Flying Carpet."

After a stint in aviation law at Paul, Weiss, he switched to literary matters and, later, to trusts and estates. In addition to Nabokov and Motherwell, his clients included Theodore H. White, The Saturday Review and its editor Norman Cousins, and Arthur Miller.

In 1961 Mr. Iseman was part of the beginning of a national educational telelvision network, serving as counsel for an educational broadcaster when it acquired Channel 13 in New York. He also worked on the formation of the Children's Television Workshop, which originated "Sesame Street." In 1968 he represented Nabokov when he switched publishers after the publication of "Lolita."

Mr. Iseman became a trustee of Bennington College in Vermont in 1969. In January 1976 he became acting president after Dr. Gail Thain Parker resigned in a dispute with the faculty. He declined to be considered for a permanent appointment, but after helping restore peace on campus, he delivered the 1976 commencement speech, in Latin, without notes.

He then moved to Paris to tend to the European practice of Paul, Weiss, and became a trustee of the American University.

Until his death, he was associated with the Hastings Center, a biomedical research institution, and Safe Horizon, an agency assisting victims of violence and their families.

Mr. Iseman was married twice. Both wives, the former Marjorie Frankenthaler, from whom he was divorced, and the former June Bank, predeceased him. He is survived by two sons, Peter A., of Washington, and Frederick J., of Manhattan; a daughter, Ellen M., of Manhattan; two stepdaughters, Anne Hamilton of Denver and Susan E. Hamilton of Scarsdale, N. Y.; a stepson, William C. Hamilton of Rye, N. Y.; his companion, Eleanor Munro Kahn of Manhattan; three grandchildren; and six step-grandchildren.