He rides his bicycle to work every day. He volunteers each year to be on call on Christmas. He hands out full-sized candy bars on Halloween. He has terrible handwriting, even for a physician. During times of uncertainty, he’s who everyone looks to for leadership.

A retirement party Monday afternoon for Dr. Henry Nieder abounded with memories, anecdotes and tributes for the longtime family physician and former chairman of primary care at the Martha’s Vineyard Hospital. For many, it was hard to believe they were saying goodbye to a doctor who has been a hospital mainstay.

“It’s surreal, I have to admit, because Henry is such a presence in the office and in our lives. He’s been a mentor to me and my friend and my boss,” said colleague and nurse practitioner Katie Friedman. “I’m thrilled for him, but it still is strange to me when he’s not at his desk.”

Since 1988, Dr. Nieder always been on call. — Mark Alan Lovewell

Ms. Friedman recalled how Dr. Nieder took time to teach her, even in the middle of a busy day.

“He had an incredibly busy practice with a number of sick patients, but he always took the time to come see a patient with me,” she said.

Wearing scrubs and loading up on fruit at the dessert table, general surgeon Dr. Richard Koehler said he had worked with Dr. Nieder for 24 years.

“I think he’s incredible. He’s the last of a generation of primary care providers who knew every single patient. He was in the hospital when they were admitted,” Dr. Koehler said, adding: “He’s particularly known for his quiet wisdom.”

Hospital president and chief executive officer Denise Schepici said she relied on Dr. Nieder as she learned the ropes after she began the job last January.

“He brought an amazing level of love for the community and professionalism to the practice. And he has a great sense of humor,” Ms. Schepici said. “He’s the epitome of the way we want to deliver care.”

Dr. Nieder has been guiding the transition of his practice to Dr. Amar Luzic, who began working at the hospital earlier this year.

“He has a wonderful practice,” Dr. Luzic said. “You see like three generations of one family, and you see them in a week.”

Dr. Luzic completed part of his residency with Dr. Nieder in 2015.

“He was a great mentor. He knows his patients really well,” Dr. Luzic said.

Gathered in the main lobby of the hospital, a number of Dr. Nieder’s colleagues made speeches in his honor while he chuckled quietly, hands behind his back. Dr. Pieter Pil said per tradition, the hospital would give him a hardwood chair engraved with the hospital logo to honor his work, but for this doctor, the gift might go unused.

“He’s not the kind of person to sit down,” Dr. Pil said. “When he’s 90, it will serve him well.”

In light of that, he gave Dr. Nieder a rare fountain pen, originally a gift from a patient whose life was saved at the hospital.

Dr. Julie Stunkel thanked Dr. Nieder for his leadership through a series of transitions, including the change to a hospital-owned practice from a private practice, and a recent switch to an entirely new data entry system. She added that his leadership manifests in smaller ways too, saying it’s thanks to Dr. Nieder that there are now umbrellas at the outdoor lunch tables, and staff showers.

“We call him our fearless leader, and we really mean it,” she said.

In a short speech, Dr. Nieder offered gratitude to the many people he worked with at the hospital since starting in 1988. He recalled relying on guidance from his colleagues to respond to his first case of arrhythmia, and the first time someone came in with a fish hook through a finger.

“Everything I did really was done as part of a team,” he said.

After the formal toasts were through, a queue of hospital staff formed to say farewell to Dr. Nieder. As with his patients, he took time with each one, focused entirely on the conversation at hand.