William Osborne Smith was born about 1833 in West Glamorgan, Wales.

He was an army officer and police commissioner. He received a military education and was commissioned into the British Army's 39th Foot Regiment in 1855. He served in the Crimean War and came to Canada with his regiment in 1856. In Montreal, he organized the Victoria Rifles in 1861 and became Lieutenant-Colonel. When his unit was transferred to Bermuda in 1859, Smith sold his commission and became a merchant in Montreal. He later became a Lieutenant-Colonel in the Canadian Militia. After some years of military service, Smith came to Manitoba in 1872 and became Deputy Adjutant General for Manitoba and North-West Territories. From September 25 to October 17, 1873, he served as the first Acting Commissioner of the North-West Mounted Police. He resigned from his post in 1881 and moved to Winnipeg, where he ran unsuccessfully for a seat in the House of Commons in 1882 and a seat in the provincial legislature in 1886. During the North West Rebellion in 1885, he raised the Winnipeg Light Infantry Battalion, later known as the 91st Battalion. In 1874, he was founding President of the Manitoba Club and, in 1879, a founding member of the Manitoba Historical Society.

In 1858, he married Janet Colquhoun. He died on May 11, 1887, while visiting Swansea, Wales.