Walsh was born in Upper Canada in 1840. He served in the Militia, reaching the rank of Major, a title that stuck with him all his life. He was one of the original nine officers of the North West Mounted Police, receiving his commission on 25th Sept 1873. During the March West he commanded 'D' Troop. He was at Fort Macleod in 1875 and ordered to take 30 men of 'B' Troop to build a fort in the Cypress Hills. This was sited at Battle Creek and completed in July 1875. He commanded 'B'Troop for 5 years.
The Wood Mountain area, within Walsh's jurisdiction was chosen by Sitting Bull and his 5000 Sioux Indians as a place to seek refuge from US soldiers. Walsh spent so much time with the Sioux that he was rarely at Fort Walsh. He liked to dress less formally and adopted the hat and buckskin seen here. He also sported a goatee beard called an Imperial after Napoleon III of France. This became fashionable amongst his men and any Mountie wearing such a beard was identified as belonging to 'B' Troop. Walsh died in July 1905 in Brockville, Ontario.