John was born in Lachine, Quebec in 1941 and moved to Whitby with his wife Beatrice in 1968. In 1969, John became involved with the sport of lacrosse, beginning an association that endured for more than 30 years.
A local sports writer once noted that "DesRosiers is one of the people who make sports tick in Durham". John has held positions of coach, trainer, timekeeper, executive member, treasurer, and director of a variety of Durham-based sport associations.
In 1993, John was the recipient of the President's Award from the Ontario Lacrosse Association. Over the course of his career, John has received championship rings from both the Ontario Junior B and Canadian Lacrosse Championships, as well as 2 Minto Cups and 5 Mann Cups. One of John's proudest moments originated from his affliation with the 1980 CBC Builders Junior A Minto Cup Championship Lacrosse team.
John also dedicated his time and extended his talents to hockey and soccer throughout the Durham Region and beyond.