John is a full time specialist periodontist who restricts his practice solely to the treatment of periodontal diseases at Park St Perio. He also teaches part time for the University of Sydney, with an appointment as an Adjunct Associate Professor.

John was previously Head of the Discipline of Periodontics at the University of Sydney with a half time appointment, while being also engaged in half time specialist periodontal practice. Prior to specialising he spent 10 years in general practice. He was also for many years an officer in the RAAF Specialist Reserve with the rank of Wing Commander.

John has also been involved extensively in other professional activities including dental regulation with the Dental Board and Dental Council of NSW and has been a council member of the Australian Dental Council where he was also involved in the assessment of overseas trained dentists. He has also been extensively involved in the provision of continuing education development for dentists with both the University of Sydney CPD and the Australian Dental Association.