John was elected as an Ulster Unionist Party MLA for East Antrim in 2017. He is the Ulster Unionist Party spokesperson on the Committee for the Executive Office.
Before his election to the Assembly, John served as a Councillor representing Carrickfergus since 2011. John also serves as a Reserve Army soldier with the North Irish Horse. He graduated from Cardiff University with a degree in History and has a particular interest in military history. In 2016 John published his first book, The Carrickfergus Roll of Honour, and donated all profits to the Royal British Legion. He is a keen cricketer playing for Carrickfergus Cricket Club and enjoys following Carrick Rangers, Tottenham, and Northern Ireland.