Cormack started competing in Gaelic singing competitions when he was 8 and competing at Mods when he was 11. He won the coveted gold medal at the Motherwell Mòd in 1983 at the age of 18, the youngest individual ever to do so.
He is part of the Gaelic supergroup Cliar and he also runs his own Macmeanmna label and continues to guest star on the albums of Blair Douglas. At the 2011 Scots Trad Music Awards, Cormack received the "Hamish Henderson Services to Traditional Music Award".
Cormack is a strong advocate for the Scottish Gaelic language. In 2009 he was appointed as the chairman of Bòrd na Gàidhlig, having been the organization's interim chairman since the previous year, as well as Chief Executive of Fèisean nan Gàidheal for many years. He was a proactive chairman, often taking to internet forums to counteract anti-Gaelic sentiment. He stepped down in March 2012. He was also formerly on the Board of Directors of Eden Court Theatre in Inverness and the Scottish Arts Council.
Cormack lives in Portree with his wife Shona. They have three children, Ruairidh, Eilidh and Iain. Eilidh and Ruairidh are both also singers, having won the women's gold medal and men's Traditional gold medal at the Inverness Mòd in 2014 respectively. Ruairidh also won the men's gold medal at the Dunoon Mòd in 2018. Eilidh is also a member of Scottish traditional band, Sian.
- Nuair a Bha mi Òg (1984)
- Ruith na Gaoithe (1989)
- Buanas (2018)
- Gun Tamh
- Grinn Grinn
- Lasair Dhe
- HI-Arts: October 2003 Feature: Arthur Cormack[permanent dead link]
- Foot Stompin: Nuair Bha Mi Og
- "Record numbers vote at Trad Music awards". The Oban Times. 5 December 2011. Retrieved 11 March 2012.
- "Bòrd na Gàidhlig chair appointed". Scottish Government website. 22 February 2009. Retrieved 28 January 2012.
- "Bòrd na Gàidhlig Chair resigns". Stornoway Gazette. 7 March 2012. Retrieved 7 March 2012.
- "No. 61092". The London Gazette (Supplement). 31 December 2014. p. N12.
- 2015 New Year Honours List
- "Here's for the competition – and Dunoon's scenery". The Press and Journal. 18 October 2018. Retrieved 31 December 2018.