The green-eyed TV star with the beauty mark on her cheek shows up at a school on the Upper East Side of Manhattan every Wednesday. For an hour, Ms. Tina, as the students and teachers call her, devotes herself to a pair of 7-year-olds who are struggling with reading. They’ll go through whatever books the teacher gives her, like “All Aboard!” or “How to Catch a Witch.” When her time is up, she’ll head home.

None of the children will have any idea that Ginger from “Gilligan’s Island” — in real life, the actress Tina Louise — just spent the best 60 minutes of her week with them.

Ms. Louise does not like to talk about the television show that made her a household name. She has no desire to revisit the years between 1964 and 1967, when she was marooned with six oddballs and a trunk full of slinky, sequined gowns.

Through its run of 98 episodes, “Gilligan’s Island” was a prime-time success and became a Gen X touchstone in reruns. (The question of “Ginger or Mary Ann?” can still evoke passionate debate among men of a certain age.) As for Ms. Louise, she can barely utter the name of the program, referring to it as “G.I.” or “The Series.”

It’s not that she regrets it, although she and the cast never received residuals. “I’m very grateful for all the things that have happened to me and the opportunities that I’ve had,” she said in a recent conversation from her modest one-bedroom apartment in Manhattan. She is the show’s last living cast member, and she recently celebrated a birthday she’d prefer not to discuss. (“I’m 29,” she said coyly.) She still has the signature beauty that made her famous, now on display in jeans and a black T-shirt instead of fancy gowns.

There were few signs that her apartment was the home of a TV icon. There were three paintings of her from her “Island” days and a glamorous shot at her wedding to the radio announcer and TV host Les Crane (they divorced in 1971, and he died in 2008). But the shelves were mainly lined with photos of her daughter, the novelist Caprice Crane, and twin grandchildren.

She regularly receives fan mail, which she appreciates, and she’s often recognized on the street. Still, she refuses to be defined by her Marilyn-Monroe-meets-Lucille-Ball-meets-Jessica-Rabbit role. “I’d like to be known for other things,” she said.

Those other things include a role in the 1958 drama “God’s Little Acre,” for which she won a Golden Globe; a solo album, “It’s Time for Tina,” in which she breathily sang classics like “I’m in the Mood for Love” and “Embraceable You”; studying with Lee Strasberg as a member of the Actors Studio; five Broadway plays, including “Fade Out — Fade In,” with Carol Burnett (which Ms. Louise left to join “The Series” in 1964).

Post-“Gilligan,” she appeared in the original “The Stepford Wives” in 1975, and later wrote two children’s books. She also published a memoir, “Sunday,” in 1997. (The audiobook version, which she read, came out in 2023.)

It is not a gossipy dish on life in Hollywood; she’s not interested in that. “You can write whatever you want about me when I’m dead,” she said.

Instead, “Sunday” covers three very unhappy years a girl named Tina Blacker spent in the Ardsley Heights Country School and Camp for Girls, a boarding school in Ardsley-on-Hudson, N.Y.

The place seems Dickensian at best. When Tina is caught talking with a friend late at night, a teacher makes her stand alone in a dark bathroom with spiders crawling on the ceiling. Her closest friends may be the caterpillars she hides in a box beneath her bed. She recounts the time another student stabbed her in the wrist with a pencil, leaving a faint scar she still has.

“We were just little angry girls that were put in this place, and nobody wanted to be there,” she said.

Her mother, Sylvia Horn, was 18 when Tina was born; her father, Joseph Blacker, was 10 years older. By the time Tina was 4, her parents had divorced. Unable to care for her, her mother sent her to Ardsley. Sunday, visiting day, was the only bright spot, but her parents didn’t always come. Once, they arrived on the same day and a vicious fight ensued. Tina’s loneliness was palpable. “I didn’t have hugs,” she said. “I didn’t have loving situations.”

She left Ardsley at 9 and moved in with her father and his new wife. She was happy. It was her first real home, and she longed to stay there. But when Tina was 11, her mother, who by that time had married a wealthy doctor — the third of her four husbands — wanted her to live with them in their fancy townhouse on the Upper East Side.

“It was like going from ‘A Tree Grows in Brooklyn’ to ‘Eloise at the Plaza,’” said Ms. Louise, adding that she had no memory of living with her mother before that point. Once she settled in, her mother had her call her father and tell him that it was best that they not get together anymore. Tina didn’t see him again until “God’s Little Acre” came out, by which time she was now Tina Louise, a starlet on the verge.

She never forgave her father for not fighting for her. “I was mad at him because he didn’t go to court,” she said.

She has a better understanding of her mother, whose own mother died when she was 3. “She didn’t have the loving that she needed,” she said. “She always needed a man to lean on.” Her mother never wanted to talk about what happened to her at Ardsley. For years, Ms. Louise said, she felt as though she was gagged. But her time at Ardsley has also fueled her support for literacy and reading with children.

In 1996, after seeing an article about a drop in students’ ability to read, Ms. Louise joined Learning Leaders, a nonprofit that trained volunteers to tutor public school students throughout the five boroughs. For the next two decades Ms. Louise diligently worked with students, encouraging them in a mellifluous voice.

Some of the teachers were familiar with her pedigree, but the students weren’t. Ms. Louise recalled the young boy who raised his hand when the teacher asked if anyone knew who she was.

“She’s the lady who talks to us and reads to us,” he said.

“I loved it, being anonymous, just being the person who read to the children,” Ms. Louise said. “That was very important to me because nobody ever read to me.”

After the organization lost its funding a few years ago, Ms. Louise reached out to the principal of the school where she attended seventh and eighth grade to see if there was any way she could help on her own.

Ms. Louise goes to the school rain or shine. “I love being in their presence for an hour. It’s better than vitamins,” she said. “I can’t get back what I went through, but outside of being with my family, doing this is my special thing.”

Her work with the children also inspired her to write two books: “When I Grow Up” and “What Does a Bee Do?” The bee book came after a conversation with some students.

“I asked them, ‘Do you know what the bees do?’ And everybody said, ‘Sting!’ And then I said: ‘No, no, they don’t. It’s the wasp that stings. The honeybees don’t do that. They feed us. They give us all these vegetables and fruits,’” she said.

Unknowingly, Ms. Louise had drawn a link between her old and new lives. On an episode of “Gilligan’s Island,” Ginger, Mary Ann and Mrs. Howell formed a pop group called the Honeybees. Reminded of this, Ms. Louise was silent for a moment, then she giggled.

“That’s funny,” she said. “I forgot about that.”