SEDGWICK — By his own admission, Clinton Trowbridge got into writing as an occupation relatively late in life.

Trowbridge, now 85, attended Princeton and then the University of Florida to get his Ph.D., but it wasn’t until he was in his forties, when he had the summer off from his college teaching job, that he first felt compelled to try his hand at writing something other than an academic paper.

So in the late 1960s he wrote “The Crow Island Journal,” about his experiences living for a summer in a tent on a tiny island off the Deer Isle community of Sunshine. The manuscript got passed through a series of relatives and family friends to an executive at Harper & Row, a major publishing firm that published it in 1970.

“That completely spoiled me,” Trowbridge said Friday, sitting in the study of his home on Old County Road. “I started at the top without any effort. I thought, ‘Hot dog! I’ll be Tolstoy!’”

Trowbridge learned to temper his expectations. He wrote four more books over the next 43 years, but none became bestsellers and he barely got paid anything for his writing, he said. He managed to get by on his earnings from teaching English at Dowling College, College of Charleston and College of the Atlantic.

But despite his being well past retirement age, his career could be in for a boost. HBO has obtained the film rights to his second book, “The Man Who Walked Around the World,” and has hired a screenwriter to develop a script. Trowbridge said Friday that this doesn’t mean the movie will get made, but if it does he could stand to earn $30,000 or $40,000 from it.

“It’s still peanuts,” he said with a chuckle of the potential payday. “[But] I’d be delighted if HBO puts it out.”

Trowbridge said it was a stroke of luck by which he got involved in the book project to begin with. “The Man Who Walked Around the World” is a true story about David Kunst’s four-year trek around the globe from 1970 to 1974.

Kunst, a Minnesota man, set out on foot from his home with his brother, John Kunst, and a pack mule in June 1970. John Kunst died during the journey, when the pair was shot by bandits in Afghanistan, but David Kunst survived and persevered. Another brother, Peter Kunst, later joined David for part of the trek through Asia. Three pack mules and dozens of pairs of shoes later, Kunst made it back to Minnesota in October 1974.

Trowbridge said he did not know Kunst, but always has been intrigued by adventurers. About a year after Kunst returned home, Trowbridge was thumbing through a copy of the Guinness Book of World Records, looking for something to write about, when he came across Kunst’s accomplishment.

“I called him up as soon as I read it,” Trowbridge said.

After telling Kunst who he was and why he was calling, Kunst told him he had been working on a manuscript about his journey but had hit a dead end. Trowbridge then went out to Minnesota and interviewed Kunst for a week.

“He’s not a writer,” Trowbridge said of Kunst, who still lives in Minnesota. “[Kunst’s manuscript] was chronological and boring. He didn’t know what to emphasize.”

Trowbridge’s luck in co-authoring the book with Kunst was in his timing. A week after Trowbridge’s visit, a writer with Sports Illustrated contacted Kunst and offered his help.

“He had already committed to me,” Trowbridge said of Kunst. “That was another stroke of luck — an incredible stroke of luck.”

The book was published by William Morrow & Co. in 1979.

“It got some attention, but not very much,” he said.

Trowbridge’s next book — another true travel adventure tale about cyclist Ian Hibbell — came out in 1984, for which he was paid the grand sum of $700. In the 2000s, he put out two memoirs, one about his teenage years at Groton School and another about his adventures with an old sailboat, through a small publishing outfit owned by a friend.

“But then [in the late 2000s] HBO called up and notified Kunst and we made a deal and they’ve been paying us $1,000-plus apiece for the last four years just to hang on to the book,” he said.

Trowbridge said it would be a fitting end to his “impulsive” and “crazy” career as a writer and minor adventurer if HBO makes a film of “The Man Who Walked Around the World.” It would be even better, he said, if people like the movie and it renewed interest in the book.

“Luck has an awful lot to do with things. There’s a certain craziness involved in the whole business,” Trowbridge said. “I hope I live long enough to see it get made.”