Marian Sulzberger Heiskell, a New York civic leader and philanthropist, who led campaigns to create the Gateway National Recreation Area and restore the grandeur of theaters on 42nd Street, and who was a member of the family that controls The New York Times, died March 14 at her home in Manhattan. She was 100.

As the granddaughter, daughter, wife, sister, aunt and great-aunt of six successive publishers of The Times, and as the wife of Andrew Heiskell, the chairman of Time Inc., Mrs. Heiskell moved in the circles that dominated New York’s philanthropic and social world.

Marian Effie Sulzberger was the last surviving member of her generation of the Sulzberger family. Her siblings were Ruth Sulzberger Holmberg, who was the publisher of The Chattanooga Times for 28 years, and who died in 2017; Judith P. Sulzberger, a physician, who died in 2011, and Arthur Ochs Sulzberger, who died in 2012. He was publisher of The Times from 1963 to 1992 and chairman and chief executive of the company from 1973 to 1997, when he became chairman emeritus.

Mrs. Heiskell stepped down as a director of The Times in 1997, but remained a principal owner of the company under a trust that passed to the four children that was intended to preserve family control of the company. In succeeding years, Mrs. Heiskell maintained an office at The Times, dining in the cafeteria with staff members and conferring with her brother, the chairman  emeritus, and her nephews, Arthur Ochs Sulzberger Jr. and Arthur Gregg Sulzberger.