During his time with the Jets, McKinstry worked full-time on the off season for Grumman Aerospace Corporation in Bethpage on the project management team.
While working nights at Grumman, he obtained a Bachelor of Science degree in health and physical education at LIU Post in 1976, graduating with the designation of cum laude.
Expanding on his graduate thesis in speed development, McKinstry launched his own business, Nu Tek Athletic Consulting Ltd, in 1986.
During his four years he taught SIE VII special education students, earning a tenured teacher appointment.
McKinstry now volunteers at various organizations, such as the Intrepid Sea, Air & Space Museum, teaching young children about the benefits of education while pursuing their interest in sports.