Robert Douglas Rorison was born on September 10, 1848, in Fitzroy Township, Carleton County, Ontario.

He was a businessman and philanthropist. He was educated at Belleville College and London Commercial College in Ontario. He taught school for several terms before entering the business. In 1879, he joined the great migration to the then-new province of Manitoba. He was first a grain dealer in Carberry and later began business as a commission merchant in Winnipeg, becoming its leading businessman. In politics, his sympathies were with the advanced Prohibitionists. He served as a Secretary of the Manitoba Branch of the Prohibition Alliance and an editor of The Banner, the leading Prohibition journal of Manitoba. In 1893, he also entered the real-estate business. In 1899, he moved to Vancouver, forming the firm R. D. Rorison & Son, handling city property and becoming interested in timber, lumber, and mining enterprises. In 1909, they organized the Royal Nurseries and Floral Company, Ltd. with a capital stock of one million dollars. He was a member of the Royal Templars Society and the good Templars Society. He generously supported the Young Men's and Women's Christian Associations.

In 1875, he married Charlotte Walford (1847–1909), and in 1911, he married Jane "Jennie" Kilby (1861–1941). He died on October 5, 1934, in Vancouver, British Columbia.