Niall studied dentistry at the University of Edinburgh and then medicine at the University of Wales College of Medicine, Cardiff, undertaking junior doctor posts in Edinburgh, Cheltenham and south Wales, before undertaking specialist training in Oral & Maxillofacial Surgery in Wessex. During his junior doctor rotations he successfully completed the Fellowship in Dental Surgery and the Membership in Surgery Examinations at the Royal College of Surgeons of Edinburgh.
At the end of his specialist training he completed the Fellowship to the Royal College of Surgeons in Oral & Maxillofacial Surgery. He finished his training with a period as a fellow in Reconstructive Cosmetic Surgery in Wessex. He is registered as a specialist in Oral & Maxillofacial Surgery with the General Medical Council and a specialist in Oral Surgery by the General Dental Council, and is a fellow of the British Association of Oral & Maxillofacial Surgeons.
He is on the editorial board of the British Journal of Oral & Maxillofacial surgery, and in 2015 was honoured to be invited to be a member of the Strasbourg Osteosynthesis Research Group, an international collaborative academic group in Oral & Maxillofacial Surgery, and invited to lecture internationally. He is also an examiner for the Membership in Oral & Maxillofacial Surgery for the Royal College of Surgeons of Edinburgh.