He was educated at Ottawa and at University of Trinity College at the University of Toronto. Parker started as a teacher at the Ontario School for the deaf and dumb (in Belleville, Ontario). From there he went on to lecture at Trinity College. In 1886 he went to Australia, and became for a while associate editor of the Sydney Morning Herald. He also traveled extensively in the Pacific, Europe, Asia, Egypt, the South Sea Islands and subsequently in northern Canada. In the early nineties he began to make a growing reputation in London as a writer of romantic fiction.
The best of his novels are those in which he first took for his subject the history and life of the French Canadians; and his permanent literary reputation rests on the fine quality, descriptive and dramatic, of his Canadian stories. Pierre and his People (1892) was followed by Mrs. Falchion (1893), The Trail of the Sword (1894), When Valmond came to Pontiac (1895), An Adventurer of Icy North (1895), and The Seats of the Mighty (1896, dramatized in 1897). The Seats of the Mighty was a historical novel depicting the English conquest of Quebec with James Wolfe and the Marquis de Montcalm as two of the characters. The Lane that had no Turning (1900) contains some of his best work. In The Battle of the Strong (1898) he broke new ground, laying his scene in the Channel Islands. His chief later books were The Right of Way (1901), Donovan Pasha (1902), The Ladder of Swords (1904), The Weavers (1907), Northern Lights (1909) and The Judgment House (1913). Parker had three that made it into the top 10 on the annual list of bestselling novels in the United States two of which were on it for two years in a row.
In 1895 he married Miss Amy VanTine of New York, a wealthy heiress, daughter of Ashley VanTine. His Canadian connection and his experience in Australia and elsewhere had made him a strong Imperialist in politics, and from that time he began to devote himself in large measure to a political career. He still kept up his literary work, but some of the books last mentioned cannot compare with those by which he made his name. He was elected to the British House of Commons as a Conservative member for Gravesend and remained MP until 1918.
He was knighted in 1902 for his service to Canadian literature, and in succeeding years continually strengthened his position in the party, particularly by his energetic work on behalf of Tariff Reform and Imperial Preference. During World War I he organized British publicity toward the United States. He was appointed as a Privy Councillor in 1916.
In May of 1905, Parker publicly claimed to have seen a "vision" of fellow house member, Sir Frederick Rasch, despite the fact that Rasch had passed on, of an illness at his home.
On September 26, 1932 he was buried in Belleville, Ontario. One of the honorary pallbearers was then Prime Minister of Canada, Richard Bedford Bennett.
Toronto Star, Sept. 27, 1932, The Times, September 7th, 1932, 14b