Jennifer Raab, a former chairwoman of the Landmarks Preservation Commission and now the president of Hunter College, called Ms. Matz “a persistent watchdog with a laser focus on New York City’s architectural gems.”
Sometimes she was paid for her work on preservation campaigns, sometimes not.
“My ex-husband said I was a philanthropist, because I really would have done some of those for nothing,” Ms. Matz, who was divorced from the publicist Mortimer Matz, said in an interview in 2007 with the New York Preservation Archive Project. “I just loved a good fight.”
Among her successful fights was a campaign in 1978 to grant landmark status to the interior of the Town Hall, an auditorium in the theater district, and, in 1990, to City and Suburban Homes, a complex of model tenements on the Upper East Side.
Two other successful fights, in the 1980s, preserved one Park Avenue landmark, Lever House, and part of another, St. Bartholomew’s, which was seeking to replace its community house with a 47-story office tower.
In those campaigns she collaborated with Jacqueline Onassis, who at one point attended a news conference in Albany while making clear that she did not want to answer questions.
“She said, ‘Don’t want to talk to the press,’ ” Ms. Matz recalled. “I said, ‘O.K.’ We held a news conference, we’re all sitting up there, she’s sitting up there, and they start to ask her questions. What’s she going to do? She had to answer. She was wonderful. And then she stood and had her picture taken with every single legislator.”
Joyce Carol Arnstam was born on May 20, 1925, in Manhattan to Harold Arnstam, who ran the fur departments for a department store chain, and the former Elsie Corday.
After graduating from the Fieldston School, she earned a bachelor’s degree in English from Mt. Holyoke College and did postgraduate work at Smith and Barnard.
In addition to her daughter Suzanne, she is survived by another daughter, Linda, and a son, John — all from her marriage to Mr. Matz — as well as three grandchildren.
Ms. Matz was involved in efforts that modestly pared down Mr. Trump’s proposed Trump City residential development on the West Side of Manhattan in the 1990s, but she balked when other civic groups agreed to a compromise.
“How much would Trump have to offer me for me to work with him?” Ms. Matz asked. “A million? Two million? Five million? I’m lucky I don’t need the money. It changes your whole perspective on things, when you have a family to support and the money’s tight and you need to pay the mortgage. I don’t have that. It’s very easy for me to be honest.”
Her involvement in preservation began with buildings she had never seen.
“I read an article in National Geographic that Venice was sinking an inch a year, and for some reason I panicked,” she once recalled. “I thought, ‘I won’t get there in time to see Venice.’ So I ran over to Italy with both my children, two different trips, and saw Rome and Venice and Florence and became enamored with buildings.”