In 2014, when he last feted her, Mayor de Blasio said of Mrs. Sansone: “No matter how much the times change, she is relevant to the times, because of the way she lives. There are some great people whose time passed them by. Mary is urgent and vibrant to this day.”

As hundreds of her fans prepared to personally congratulate her on Tuesday night at the Dyker Beach Golf Course in Brooklyn, Mrs. Sansone complained that the world had become more hypocritical and that people were afraid to tell each other the truth.

Still, she said, “Let me tell you, it’s not bad to be 100.”

“My biggest accomplishment was that I had the strength to do what I wanted to do and stand up for what I believed,” she added, “As my father said, when you die, you can’t take your money with you. You can only take your integrity.”

At the celebration, Mr. de Blasio proclaimed Mary Sansone Day in New York, and former Mayor Michael R. Bloomberg presented Mrs. Sansone with a T-shirt emblazoned with “Bloomberg/Sansone 2016” and the slogan “A Meatball in Every Pot.”