[1] He is best known for setting up the publishing house Gairm, along with its magazine, which was the longest-running periodical ever to be written entirely in Gaelic, running for over fifty years under his editorship.
[1] Thomson was originally from Upper Bayble (Pabail Uarach) on Lewis, the same village that produced two other Gaelic writers of note, Iain Crichton Smith and Anne Frater.
He published seven collections of Gaelic poetry, with many English translations, including Meall Garbh/The Rugged Mountain (1995), Smeur an Dochais, etc.
He was elected Fellow of the British Academy in 1992 and gave the 1999 Sir John Rhys Memorial Lecture on "Scottish Gaelic Traditional Songs from the 16th to the 18th Century".
[5] Thomson was also tireless in his support of other writers in Gaelic and helped bring to publications works such as 'Gaelic Verbs' by Colin B.D.