When the artist Jordan Casteel arrived on campus as a college freshman, her mother marched her into the dining hall — not for a meal, but to greet the kitchen staff. They had met the president and dean, but these were the people, her mother explained, who would truly be taking care of her.

Ms. Casteel recalls being shy, but her mother was right: The first person she approached, a baker named Betty, became a surrogate parent. “She cooked me Sunday meals, would bring me birthday cakes,” said Ms. Casteel. Nearly a decade later, they still talk on the phone. “There’s really something magical that can happen when you take that risk,” she said.

This particular alchemy, the kind that begins with a nervous hello and transforms strangers into family, lies at the core of Ms. Casteel’s practice. Nearly 31, she has attracted widespread acclaim for colossal portraits of friends and neighbors, works celebrated for their tenderness, keen social commentary and technical brio. Her first institutional show in New York — an exhibition of nearly 40 canvases spanning seven years — opens at the New Museum on Feb. 19.

“What we see when we look at one of Jordan’s portraits is her ability to represent her subjects in their fullness,” said Thelma Golden, the director of the Studio Museum in Harlem, where Ms. Casteel completed a residency in 2016. “She is able to capture a sense of spirit, a sense of self, a sense of soul.”