He worked as a journalist with Joseph Howe on the Novascotian during the 1840s. In 1847, he became the owner of the Eastern Chronicle at New Glasgow. He served as Queen's Printer for Nova Scotia from 1860 to 1863. In 1863, he founded the Halifax Citizen with William Garvie; the paper favoured a maritime union but opposed Confederation. McDonald and Garvie also helped found the Anti-confederation League, which had the same aims.