He travelled to Britain to study at the University of Glasgow where he graduated with a Master of Arts (Divinity) and was ordained as a Presbyterian minister in 1911.
He initially ministered at Minard in Argyll and Bute but returned to New South Wales and took locum appointments at Coonamble, Gilgandra and Ultimo before being given a permanent position at Scots Kirk, Mosman in 1915.
The next year, Macdonald was given leave to serve as a chaplain with the First Australian Imperial Force in France, where he was awarded the ED.
[2] He entered parliament as the Independent UAP member for Mosman after winning the seat at the 1941 state election.
He did not hold parliamentary or ministerial office,[1] but was said to be only the second active ordained Christian minister in the Legislative Assembly since the Reverend J. D. Lang.