After the war Banks resumed his career in the mining industry. Among other ventures, Banks co-founded the Placer Development Co., later Placer Dome, which was acquired by Barrick Gold in 2006. In 1937, the Mining and Metallurgical Society of America awarded its Gold Medal to Banks for his role in the aerial development of remote mines.
During World War II, Banks served in London as the representative of the Canadiangovernment. His duties included management of the transportation of supplies for the war effort. His wartime service earned Banks the C.M.G..
Ross was appointed as Lieutenant-Governor on 1 October 1946 and served in that office for four years. After his term in office, Banks relocated to Vancouver where he lived until his death in 1961. Amongst the bequests in his will was a $1.1 million gift to the University of British Columbia used to establish a fund for needy students in his and his wife’s name.