His first role in the clergy was as assistant to Paul Fraser at Inverary Parish Church and then assisting Angus McLain at the same church. In April 1828 he was ordained as minister of the parish under the patronage of George William, Duke of Argyll in place of NcLain who translated to another parish. In August 1831 he translated to the neighbouring parish of Glenaray his place at Inverary being filled by Duncan Campbell. Smith remained minister of Glenaray for the rest of his life.[1]
In 1840 he formed part of the small Committee translating the Bible into Gaelic to address the issues of the outer islands where Gaelic remained either the dominant or sole language. In December 1849 Glasgow University awarded him an honorary Doctor of Divinity.[1]