School lunches are normally casual affairs, eaten in shifts with food collected on trays. But on Thursday, more than 450 people sat down together in the West Tisbury School gymnasium for a farm-to-table meal and some live music from a school alumnus.

“The first time I played on stage, it was on this stage,” said recording artist Willy Mason, who sang and played guitar as the dining tables filled with Islanders from kindergarten age to senior status.

The community lunch is a new tradition at West Tisbury School, launched just over a year ago by chef Jenny Devivo. Thursday’s was the third in what is shaping up to be a twice-a-year event, with the next one planned for March.

Ms. Devivo said the inspiration came from the smaller Chilmark School, which periodically hosts a family-style lunch gathering at the Chilmark Community Center where students help prep the meal, set tables with real china and glassware and engage in conversation with invited Islanders.

“There was a lot of skepticism” on the West Tisbury campus, Ms. Devivo recalled, but adapting Chilmark’s event to a school four times the size was a challenge she gladly accepted.

“I’m a dreamer. I go big or go home. We jumped in with both feet, and it was magical,” she said. “All the doubting Thomases came eating crow and thanking us.”

Along with the entire school, Ms. Devivo invited community guests including local leaders, first responders, Vineyard farmers and volunteers with Island Grown Gleaning.

“They’re the heroes of this whole thing,” Ms. Devivo said of the gleaners who gather surplus produce from local growers. Some of the vegetables served at Thursday’s lunch were grown, gleaned and processed over the summer, then frozen until needed, she said.

The meal also included Island chicken from the Good Farm, kale from the school garden and a chimichurri sauce made with school-grown herbs. Dessert was housemade granola power bars, a regular treat from the school kitchen.

Cooking for a crowd is what Ms. Devivo does. Each weekday, she and her three-person kitchen team serve lunch to about 350 students and close to 100 staff at the West Tisbury School, and send more than 100 meals up the road to the Chilmark School.

But feeding such a large group in one seating required extra planning and assistance. Ms. Devivo said about 30 volunteers pitched in, including parents and volunteer chefs.

She also has a built-in labor force: the sixth-grade class, some of whom attended Chilmark School through fifth grade and have experience with community lunches from their years there.

Carefully laid with tablecloths, cloth napkins, flatware and real plates and glasses, the table settings — complete with handwritten placecards — were the work of the sixth graders, who had decorated the gym for the occasion.

Stationed one per table, sixth graders were also in charge of bringing their tables the family-style dishes to share. And after the meal, they would clean up.

“They’re studying humanity today,” instead of classroom topics, Ms. Devivo said.