As an undergraduate, Leventhal studied civil engineering, becoming a naval architect during World War II. He founded the Beacon Construction Co. in 1946, along with his brother, Robert. He is known for several signature developments in Boston, as well as for being a "tireless benefactor."
“He had a great interest in art and architecture,” said Alan Leventhal, noting that his father’s intellectual interests were well served by his committee work at MIT. “He had an enthusiasm that never left him.”