Nick Howley wasn’t a great student at St. Joseph’s Prep, but the lessons he learned there propelled him to a good life: degrees from Drexel and Harvard, a successful career in business.

“The Prep laid the learn-to-learn foundation,” said Howley. “It was there when I was ready.”

Howley on Thursday will announce the largest gift ever in history of the Jesuit college prep school, $5 million to upgrade the North Philadelphia campus and provide scholarships to low-income students.

Howley made his mark as the founder of TransDigm, a Cleveland-based aerospace manufacturing company, and has also spent the last 20 years focused on philanthropy. He and his wife, Lorie, founded the Howley Foundation, which supports primarily Catholic schools and students in Cleveland and Philadelphia.

The foundation already sponsors “Howley Scholars” at the Prep; the donation will expand that program, supporting the education of 28 boys, financially and through mentorships. The remainder of Howley’s gift will go toward the school’s $35 million capital campaign, which seeks to modernize the school, whose facilities date to the 1960s.

“For many, this is life-changing,” said the Rev. John Swope, Prep president.

Being a Howley Scholar has meant much to Sahmir Hagans, a Prep senior and football standout headed to Duke University in the fall. It made his Prep education possible, he said.

“I know that my pathway to Duke was through the Prep … and the Howley Foundation has played a big part in that,” said Hagans, who’s spent time with the Howleys as part of the program.

Howley grew up in Delaware County, the oldest of eight children. He vividly remembers the day in 1968 his mother dropped him off at the 69th Street Terminal to board the El and head to the Prep. The world was changing, much as it is today, and people at the Prep helped him understand that, Howley said.

“The faculty strove to put a very tumultuous political and social time in context for teenaged boys,” he said. “Neither of these was an easy task.”

As a Prep student, Howley didn’t imagine that his high school years would leave such a lasting impression; he was more occupied with sports than academics. But once he got to Drexel, where he studied engineering, things clicked and he graduated at the top of his class, Howley said. A Harvard M.B.A. was next.

He wasn’t much in contact with the school for 30 years. He was busy building a business, raising a family. But when the Howleys began their foundation 20 years ago, it felt right to reach back to 17th and Girard, he said.

“Lorie and I believed that the only lasting thing we could provide our children or others was a high-quality education and a sense of right and wrong, or moral compass,” said Howley, who was for years board president of the Cristo Rey network of Catholic schools in underserved communities. “We also believe that the only practical path to equity and social and economic mobility runs right through a quality education.”