Ussher went on to become Chancellor of St Patrick's Cathedral, Dublin in 1605 and Prebend of Finglas. He became Professor of Theological Controversies at Trinity College and a Bachelor of Divinity in 1607, Doctor of Divinity in 1612, and then Vice-Chancellor in 1615 and vice-provost in 1616. In 1613, he married Phoebe, daughter of a previous Vice-Provost, Luke Challoner, and published his first work. In 1615, he was closely involved with the drawing up of the first confession of faith of the Church of Ireland.