Len was born in Vermont on November 2, 1940. He was the youngest of 2 children of Henry E. and Lila (Martel) Mercure. While growing up, he enjoyed music, movies, and cars. In his childhood, he was given the gift of an erector set, and from that he learned to create and tinker, which became a lifelong hobby that earned him the nickname of 'MacGyver'.

Len joined the Air Force after high school, where he was trained in electronics. This served him well in his 30-year career with IBM. While in the Air Force, he married Judy, and had the first 2 of his children, Michelle and Henry, Jr. Later, he married Audrey, who brought Lisa with her. Together, they added Eric to complete their family.

Len was an eternal optimist, always thinking positively and seeing only the good in situations. In his later years, after many physical setbacks, he was looking forward to the time he would walk and drive again. His glass was always half full of the lemonade that he made with any lemons life handed him.