He was born in Pickigarth, Shetland Islands on April 29, 1857, the son of John Manson and Margaret Bain.[2] He came to British Columbia in 1874. In 1879, Manson married Jane Renwick. He was a director of the Call Creek Oyster Company. Manson also served as a justice of the peace.[2] From 1887 to 1895, he operated a trading post on Cortes Island with his brother John.[3] He was defeated when he ran for reelection to the assembly in 1916.[4] Manson died in Bella Coola on July 11, 1932, at the age of 75.[1]
The community of Mansons Landing on Cortes Island is named after him.[3]