Born in Thornliebank, Scotland, he emigrated to Canada in 1882 where he was employed by the Grand Trunk Railway.

In 1896 he joined William Mackenzie and Donald Mann who organized the Canadian Northern Railway (CNoR) in Western Canada.

After the federal government took control of the bankrupt CNoR in 1918, Hanna was named president of the reorganized company in September 1918.

He was appointed the first president of the Board of Directors of the Canadian National Railways in 1919.

He retired in 1922 and was appointed first chairman of the Liquor Control Board of Ontario 1927–28.