An outstanding craftsman and promoter of Canada-US union, he was said to have studied for the priesthood in Rome before coming to Canada about 1870. He worked for various papers, including the Winnipeg Times 1882-84 and Sun, 1884. As editor of the Toronto Daily Mail 1885-90, he made it perhaps the leading paper of the day, and helped to provoke its break from the control of Prime Minister Sir John A. Macdonald. The paper brilliantly promoted an outbreak of anti-French, anti-Catholic feeling in the wake of the North-West Resistance, with Farrer evidently using the campaign to alienate English Canada from Confederation.
In 1890 he transferred to the Liberal Globe as premier editor and again subtly promoted annexation. In the 1891 election, Macdonald disclosed a pamphlet - allegedly written by Farrer - as evidence of Liberal sympathy for annexation. Farrer left the Globe in 1892, worked for the annexationist movement, and later served Prime Minister Sir Wilfrid Laurier as a propagandist and agent, consistently promoting anti-imperial policies.