Dugald Buchanan was born in Balquhidder where his father ran a mill. He is reputed to have been dissolute as a young man, but then appears to have seen the light and turned his attention to running an informal school in Balquhidder. His talents became more widely recognised and he was appointed preacher and schoolmaster in Kinloch Rannoch. Until Buchanan's arrival the residents had been as likely to enjoy Sunday playing sport as attending kirk and the parish minister was only able to give a service locally every third Sunday anyway. Buchanan was able to convince the residents, at first with some difficulty, that Sabbath-breaking was not acceptable, and the area is said to have become considerably more pious as a result.
His lack of education ruled out his becoming a minister in the Church of Scotland, but he did assist the minister at Killin, James Stewart, in his translation of the New Testament into Gaelic in 1767. He also accompanied Stewart to Edinburgh to oversee the printing of the result, and while there attended lectures at the University of Edinburgh. It is said he met and was able to hold his own in debate with David Hume.
Buchanan was best known as a poet. He wrote in Gaelic and invariably on religious topics. They were usually sombre in tone, and had subjects such as the Judgement Day. It is said that he died of a fever that also killed his eight children. He is remembered by the Buchanan Monument, erected in his memory in 1883 in the centre of Strathyre.