Doug Horner worked in aviation and medicine, which involved him in his family's dental clinic's start-up and operations.
He was involved in the start-up and operations of his family's barley and oat processing mill. Before being elected to the Alberta Legislature, Horner worked in the private sector, including banking in southern Alberta and agriculture. Later he became responsible for international marketing and sales of specialty grains for ConAgra from its Nebraska office. After three years he moved back to Canada and established a trading company for agrifoods and agrifeeds for domestic and international markets. Horner has served in the Canadian Forces Reserve, and as the Minister Liaison to the Canadian Forces. 
