With a career that spans corporate offices and classrooms–and even a year in the rural villages of Belize–Mr. Len Leib brings a rare depth of experience and perspective to his role as a math and computer science teacher at Pennington.

Leib began his pursuit of computing at Brown University, where he earned a bachelor of science in computer engineering. It wasn’t until his junior year that he first encountered programming, writing code in Fortran and Pascal. Originally planning to pursue electrical engineering, he found himself drawn to the logic and creativity of software development. 

His first professional role was at IBM, working as an internal software developer during a time when massive mainframes dominated business computing. While there, he earned an MBA in information systems from NYU, supported by IBM, which also backed his pursuit of a PhD when he considered becoming a college professor. But after two years in academia, he realized he was more energized by teaching students than publishing research and subsequently left the program.

That insight led him into the world of business consulting. Along with a few friends, Leib launched a software company, JBS Computing (Jews Building Software), that created custom applications for clients like Kraft and Kellogg’s. Long before the internet transformed internal business systems, his team helped large corporations find new efficiencies through technology. Working with Hyperion Software (now Oracle) kept them busy and successful. 

Yet the desire to teach never fully went away. Inspired in part by his mother’s career as a high school educator and administrator, Leib began to consider the world of secondary education. Though he initially faced hurdles due to certification requirements in public schools, a personal family decision would chart a new course. When he and his wife, a pediatrician, began looking for a private school for their daughter, they discovered Wooster School, and it was there that Leib found his first teaching opportunity, instructing two sections of Algebra 2. 

Though he admits it was the hardest job he’d ever taken on, he also found it deeply rewarding. Teaching, he discovered, wasn’t just about knowing the content. It was about presenting it in ways that resonate with different learners. Within a year, he committed to teaching full time, handing over the reins of his company to his colleagues.

After nearly a decade at Wooster, the Leib family embarked on an extraordinary sabbatical, spending a year in Belize with Hillside Healthcare, a faith-based organization. While his wife and their colleagues provided medical care, Leib supported operations—sweeping floors, driving a bus, and designing a patient tracking system. He also helped orient visiting medical professionals, returning briefly to a teaching role in an unexpected setting.

Eventually, their journey brought them to the Philadelphia area, where their daughter was settling. During a search for private schools within an hour’s drive, Leib connected with Pennington and, since 2011, he has been a vital part of the community.

At Pennington, Leib has taught nearly every Upper School math course, with a current focus on advanced offerings like AP statistics, AP computer science, AP calculus, and Data Structures and Algorithms. He appreciates the rigor of these courses but notes that he sometimes misses working with younger students. Nevertheless, he values the opportunity to connect with a wide range of learners from diverse cultural backgrounds and he remains a mentor to many graduates pursuing fields such as computer science, engineering, and AI research.

Leib’s own life story underscores his belief that careers don’t have to follow a single, straight path. He shares with students that it’s okay to pivot and explore new fields every decade or so—advice that his son appears to have taken to heart. After several years as a software engineer at Twitter, Leib’s son trained to become a paramedic, joining his mother and wife as a healthcare professional!

Entering the teaching profession later in life, Leib brings not only enthusiasm but also a wealth of industry knowledge that informs his classroom every day. His students benefit from the insights of someone who has lived what he teaches and who continues to find meaning in every chapter of his journey.