“It’s all in the permanent record,” Dr. Cooper said, smiling.

A big man with a streetwise charm, Mr. Liautaud delivered the commencement address last year, wearing a T-shirt, blue jeans and cowboy boots. He implored the students not to emulate his own academic and behavioral missteps.

Image Mr. Liautaud donated $1 million to his alma mater and insisted that the Liautaud-Lyons Upper School bear Mr. Lyonss name. Credit... Alex Romanovsky/DLA Architects

Among students at Elgin Academy, Mr. Liautaud is regarded as something of a hero. One of them, Christopher Theodorou, 18, said he ordered food from a local Jimmy John’s restaurant for seven straight days after learning about the donation, a gesture of pride and gratitude.

“And besides,” Mr. Theodorou said, “it’s delicious.”

Mr. Lyons, 74, now retired, said he had spent many hours in the company of young Mr. Liautaud, often because he had violated some rule.

In those days, a disciplinary dean had a little more leeway, and Mr. Lyons was not afraid to capture a boy’s attention by giving his arm a bit of a squeeze. “You wouldn’t get away with any of that stuff today,” he said.

But he also had a gentleness that won over the troubled boy.

“I would just listen,” said Mr. Lyons, who learned that Mr. Liautaud’s parents were going through hard financial times while their son was in school. “He was able to confide in me. He was a pretty good kid. He was just struggling to find out who he was.”

The two men have stayed in touch. They got together for dinner just before Christmas. “You have a lot of students who become successful,” Mr. Lyons said. “But this is one who said thank you.”