John qualified from Trinity College in Dublin in 1975. After spending four years in large animal and mixed practices in Northern Ireland and Lancashire, John bought a predominantly large animal practice in Crumlin, Co. Antrim in 1979. The practice now has three surgeries with six vets working mainly in companion animal practice.

John has also held the following posts:

President of the Association of Veterinary Surgeons Practising in Northern Ireland (1993)

President of the North of Ireland Veterinary Association (2004)

Chairman of the Northern Ireland Veterinary Education Trust (1996 - present)

Board member of Veterinary Northern Ireland (2005 - present)

President of the Society of Practising Veterinary Surgeons (2007)