 Landsborough became tutor in the family of Lord Glenlee at Barskimming in Ayrshire, was licensed for the ministry of the Church of Scotland in 1808, and in 1811 was ordained minister of Stevenston, Ayrshire.In addition to his clerical duties, and while maintaining his scholarship by reading some Latin, Greek, Hebrew, French, or Italian daily, Landsborough seems to have early commenced the study of the natural history of his parish and that of the neighbouring island of Arran, which formed the subject of his first publication, a poem in six cantos, printed in 1828.He began his botanical studies with flowering plants, afterwards proceeding in succession to algæ, lichens, fungi, and mosses.