Gordon Fahrni graduated from the University of Manitoba in 1911 and ultimately became one of the leaders in the Canadian Medical community. In 1921 he helped to organize a campaign to save the debt-ridden Canadian Medical Association, then served as President of the Canadian Medical Association from 1941-1942. Fahrni was also the founder of the American Goitre Association, and became its President in 1928. He was acknowledged as an expert on goitre surgery in North America, and was also well known as a military physician. He was instrumental in the establishment of the Medical Procurement and Assignment Board for the Royal Canadian Military which helped balance medical services for servicemen abroad and civilians at home. Fahrni retired from the medical practice in 1965 after being a medical practitioner for 54 years. In 1976, Queenston House published Gordon's autobiography, "Prairie Surgeon".
Gordon Fahrni Sr's legacy lived on with his son, Dr. Gordon Fahrni and two nephews, founding director of UBC's School of Rehablilitation, Dr. Brock Fahrni and orthopedic surgeon, Dr. W.H. (Harry) Fahrni.
Fahrni was also an avid outdoorsman and golfer. On his 100th birthday, he was featured in the Score golf magazine. When he died in 1995 at the age of 108, Fahrni was Canada's longest-lived physician.