Anthony was called to the Bar in 1975 before joining Army Legal Services in 1981. He is one of the founding fathers of the Army Prosecuting Authority, a member of the Armed Forces Bill Team in the development of the Armed Forces Act 2006 and the first legal advisor to the NATO Allied Command Europe Rapid Reaction Corps Headquarters (HQ ARRC), developing policies and advising on operational matters, including rules of engagement for the NATO forces in former Yugoslavia. Subsequently, Anthony developed the concept for the ALS Operational Law Branch to provide operational legal expertise to commanders and later was the day-to-day head of the Army Prosecuting Authority.  After retiring from the army, he became a consultant in military law.