Alexander Mercherson was a native of the parish of Kilmere on the Isle of Skye. He was born about 1766. When the New Brunswick Regiment of Fencible Infantry (later the 104th (New Brunswick) Regiment of Foot) was raised in 1803, one of the recruiting parties was sent to the Highlands of Scotland. Mercherson (also spelled Murcherson and Murchison) was one of those recruited there. He joined the regiment in October 1804, probably at Inverness, at the age of 38. He may have been married at the time. His wife was Barbara Macketche, a native of Inverness. The Scottish recruits arrived in Fredericton on 20 September 1805 accompanied by seventeen women and forty-eight children. Mercherson served as a private soldier for all of his career.