He studied and graduated in law from the University of Edinburgh. In 1824 he was registered as lawyer at the Scottish bar. In October 1824 he inherited the title "Baron Carlyle of Torthorwald".
He is not to be confused with the better-known man of letters Thomas Carlyle, born a few years earlier also in Dumfriesshire. He too was connected to Irving, who introduced him to his wife, Jane Welsh. One biographer asserts that the similarities did cause confusion: "As a 'double-goer', perplexing strangers in foreign parts as well as at home, the 'Apostle' was occasionally an innocent, inadvertent nuisance to 'our Tom'."
This Thomas Carlyle (lawyer) was the author of the book Shall Turkey Live or Die? (London: Thomas Bosworth, 1854). It has been mistakenly included in the Delphi Complete Works of Thomas Carlyle available on Amazon Kindle. This work is not in the authoritative Bibliography of Thomas Carlyle's Writings and Ana by Isaac Watson Dyer (1928).