John studied dentistry at University College Cork and qualified in 1978. He spent the next twenty-two years in general practice before completing a two-year full-time programme specializing in Oral and Facial Pain Management at the University of California, Los Angeles between 2000 and 2002.
He also completed a full-time course in the dental management of snoring and sleep apnoea. John served two years as an assistant clinical professor in the Department of Orofacial Pain at the University of Southern California, also in Los Angeles. He is a member of the American Academy of Orofacial Pain.
On returning to Ireland, John established practices confined to Oral and Facial Pain Management and management of snoring and sleep apnoea in Dublin, Galway and Portlaoise.
As well as the above areas of expertise, John practices general dentistry at the Novara Dental Clinic.