Peter Martins, who picked up the mantle from the famed choreographer George Balanchine to lead New York City Ballet over the last three decades, is taking a leave of absence in the wake of a sexual harassment accusation, the company confirmed on Thursday night.

City Ballet and its School of American Ballet had started an investigation into Mr. Martins, 71, after receiving the accusation of past harassment, which was made in an anonymous letter. The two organizations jointly retained Barbara Hoey, the chairwoman of the law firm Kelley Drye’s labor and employment practice group, to conduct the inquiry.

The specifics laid out in the accusation are not known.

Mr. Martins requested a temporary leave of absence until the investigation is concluded, according to the company. The ballet’s board of directors granted the request on Thursday night.

Several former and current ballet dancers said in recent interviews that Mr. Martins was known for sleeping with dancers, some of whom received better roles because of their personal relationships with him. Two dancers said he had a bad temper and could be physically rough on occasion, pulling dancers around by the neck during rehearsals.