Nancy Lassalle, a longtime patron of the New York Ballet and its School of American Ballet, died on April 26 at her Manhattan home. She was 93 years old.

The death was confirmed by her daughter Honor Lassalle.

As a teenager, Ms. Lassalle attended the young ballet academy founded by George Balanchine and now the School of American Ballet. She wasn’t meant to be a ballerina – she was too big and too scratchy, her daughter said – but she loved the dance and mission of Balanchine and his collaborator Lincoln Kirstein. She became a lifelong patroness of ballet and a tireless promoter of Balanchine’s legacy.

She was a founding member of the boards of the city ballet and the SAB, as the school is called. She organized numerous exhibitions and events for the company, including the centenary celebrations for Mr. Kirstein in 2007.

“She was the ultimate board member,” said Albert Bellas, SAB chairman emeritus. “She was financially supportive, knowledgeable, and dedicated.”

She was also in daily, touring with the company and giving parties for the dancers in her Fifth Avenue apartment, said Kay Mazzo, who was once a solo dancer with City Ballet and now heads the school’s faculty.

“Because she was an early student at the school, she understood what Mr. Balanchine and Mr. Kirstein had in mind,” said Ms. Mazzo. “She has kept her ideals and made sure that the school stays on course over the years.”

Ms. Lassalle was editor with Leslie George Katz and Harvey Simmonds of “Choreography by George Balanchine: A Catalog of Works,” which was first published in 1983 by Eakins Press. She was also the editor of Lincoln Kirstein: A First Bibliography. (1978). In 2016, her photographs of Balanchine, who taught a two-day master class in 1961, were published as “Balanchine Teaching”, also by Eakins.

“She was a demanding person, which could be frustrating,” said Peter Kayafas, editor and director of Eakins Press. “There was a time when I was much younger when it was difficult to have a conversation with Nancy without her correcting my grammar. And then came a time when that stopped. “Not because she was tired of the exercise, Mr. Kayafas added,” It’s like I finally learned my lessons. Whenever Nancy was around, the bar was raised. “

Alastair Macaulay, former chief dance critic for the New York Times, wrote in a social media post: “The dance world has a number of generous donors, but there was one in Nancy who combined acute intelligence with a unique devotion to the two visionaries whose work she discovered in her own youth: Balanchine and Kirstein. “

Last year, the SAB launched the Lassalle Cultural Program, which allows older students to explore ballet history and gain free access to New York cultural institutions. When she died, Ms. Lassalle was the emeritus director of the city ballet and the school.

Born a privileged child in New York City on November 10, 1927, Nancy Norman grew up in a eclectic modernist townhouse filled with contemporary photography, pre-Columbian art, and a steady stream of guests, including notable figures of post-war America Culture like Alfred Stieglitz, Aaron Copland, Allen Ginsberg and Ralph Ellison. Her mother, Dorothy Norman, was a photographer, newspaper columnist, and promoter of the arts, and an advocate for social justice and political causes. Mr. Stieglitz was her mother’s mentor and lover. Her father Edward Norman was a son of a founder of Sears Roebuck.

Ms. Lassalle attended Dalton School and the Balanchine Dance School at the age of 14. Her classmates included ballerinas Patricia McBride Lousada, founding member of City Ballet, and Tanaquil Le Clercq, Balanchine’s muse and fourth wife. The three were lifelong friends.

In addition to her daughter Honor, Mrs. Lassalle survived another daughter, Diana Lassalle Turner; one son, Philip Lassalle; and five grandchildren. Her marriage to Edmundo Lassalle ended in divorce.

In 1991 Ms. Lassalle was cast by Jerome Robbins in the lead role of Mother Goose in a bizarre children’s ballet. (It wasn’t a dancing part: As Jennifer Dunning wrote in the New York Times, she was sitting in a chair on the stage when the curtain opened and dancers were spread around her.) It was a gesture that took her place in the Embodied ballet community. Ms. Mazzo said and she loved doing it.