Arbuthnot was ordained a priest at Limerick on 2 November 1794, made vicar of Annaghdown and Killascobe in 1801 and rector of Crossboyne and Kilcoleman in 1808.
Arbuthnot's priestly career began with his ordination at Limerick on November 2, 1794. He went on to hold the positions of vicar for Annaghdown and Killascobe in 1801 and rector for Crossboyne and Kilcoleman in 1808.