Plattsburgh, New York - Mark J. Donnelly, 73, of Plattsburgh, N.Y., passed away on Friday, Aug. 22, 2025, at the UVM Medical Center in Burlington, Vt., surrounded by his family. Mark was born in Plattsburgh on Nov. 13, 1951, the son of Gerald and Mary Jane (McMartin) Donnelly. A graduate of Mount Assumption Institute, Mark would go on to receive degrees in physical education from the University of Vermont, and athletic training from West Chester University.

Mark, affectionately known as Coach, or Mr. D. by many of his students, went on to teach physical education and coach a variety of sports at St. John's Academy, and in the Beekmantown School District, before spending more than 30 years serving the Plattsburgh City School District at Plattsburgh High School. The longtime educator, coach and athletic trainer dedicated his life and career to the health, safety and well-being of student-athletes at PHS, and across the North Country. Mark was known not only as a trusted medical professional, but as a mentor who took great pride in the successes and achievements of others.

In addition to his role as a physical educator, longtime track coach, and athletic trainer at PHS, Mark was active in the community and at state levels as an instructor in first aid and CPR, teaching numerous coaching safety courses, creating athletic training classes for students at PHS, and serving on New York State Public High School Safety Committees, advocating on behalf of student athletes. His legacy is seen in the students that he mentored who have gone on to serve their communities as educators, coaches, athletic trainers and professionals in a variety of fields.

When he wasn't working, Mark could be seen cruising around his hometown in his '57 Chevy. His greatest source of pride and joy was his family. He was a devoted husband, father, son, brother, uncle, and the best Grampy around. Mark has always been known for his strength; both physically, and that of his character. His integrity, work ethic, loyalty, and desire to help others are just part of his legacy.

Mark is survived by his wife and partner of 55 years Joyce Donnelly, son Patrick Donnelly and his wife Trisha, daughter Erin (Donnelly) Moriarity and her husband Sean, and his grandchildren Caitlyn and Jackson Donnelly, Isla, Finnegan, Sullivan and Macallan Moriarity, as well as his sister Cynthia (Bill) LaWare and family.

He is predeceased by his parents.

A celebration of life in Mark's honor will be held on Saturday, Aug. 30, 2025, from 2:30 to 5 at the Adirondack Room at the Butcher Block, 15 Booth Drive, Plattsburgh, N.Y.