Remarkably, Waitz, a champion track runner, ran her first marathon as a lark, with the encouragement of her husband, who was also her coach, and who told her that a trip to New York would be like a second honeymoon for them. Even in training she had never run more than 13 miles, and the science of the sport was young enough that her dinner the night before the race included shrimp cocktail and filet mignon, hardly the load of carbohydrates that even today’s rankest amateurs know to consume. As she recalled in later interviews, the last 10 miles of the race were agony, and she was so angry at her husband that when she crossed the finish line, she tore off her shoes and flung them at him.

“I’ll never do this stupid thing again,” she yelled.

She was, however, hooked. The next year, she finished the race in 2:27:33, beating her record by almost five minutes and becoming the first woman to officially run a marathon faster than two and a half hours. Her legendary status was assured.

In her home country, her New York victories conferred on her the status of a national hero; a statue of her stands outside Bislett Stadium, an international sports arena in Oslo, and her likeness appeared on a Norwegian postage stamp. She established a 5-kilometer race in Oslo that eventually expanded to 40,000 runners, and in 2007, she started her foundation, which sponsors runners in major races and supports cancer hospitals and patient centers.

“I am convinced you can go through a lot more when you are physically fit,” Waitz said to explain her foundation’s philosophy. “It is both physical and mental. With the athletic background, you think more on the positive side — you can do this.”

But she was also lionized in this country, and especially in New York, and the image of her on the road — a quick, efficient stride, her pigtails slicing back and forth like metronomic windshield wipers — became familiar.

She won her victories as the popularity of the New York marathon itself surged, and she became a celebrity in the city. Cabdrivers and the homeless called her by her first name, and over the years, she and her husband made appearances not only at the marathon but also at other New York events, including Grete’s Great Gallop, a half-marathon run each October as part of a Norwegian festival.