In 1774 he was acting as one of Peter Williamson's penny postmen; he next found employment as a copying clerk, and was subsequently tutor in the family of Stewart of Gairntully.
In 1789 James Brown, the sole representative of the nonjuring episcopal clergy of Scotland, made Macintosh as his successor, ordaining him deacon in June 1789, and later priest.
He finally settled in Edinburgh, but made an annual tour through the Perthshire highlands as far north as Banff, Aberdeenshire, ministering to the small remnant who accepted his pastoral authority.
[1] In 1794 Macintosh unsuccessfully raised an action in the court of session against the managers of the fund for the relief of poor Scottish episcopal clergymen, who had deprived him of his salary.
He died unmarried at Edinburgh on 22 November 1808, the last representative of the nonjuring Scottish Episcopal church, and was buried in Greyfriars churchyard.
[1] Walter Scott drew liberally on Macintosh's work for the Gaelicized phraseology of the character Evan Dhu Maccombich in Waverley (1814).
He collected old poetry; a piece from Lochaber in 1784, Ceardach Mhic Luin, appeared in the Sean Dain (1786) of the Perth bookseller John Gillies (p. 233).