In 1978, Mackay joined the South African Breweries Limited, holding numerous senior positions, including Executive Chairman of the beer business in South Africa. He was appointed Group Managing Director in 1997 and was the Senior Independent Non-Executive Director of Reckitt Benckiser Group plc until his resignation in June 2013.
- Phillip Morris International, Graham Mackay Elected to Board of Directors of Phillip Morris International (PMI), 31 October 2008, accessed October 2018
- P. Evans, SABMiller Chairman Graham Mackay Dies, The Wall Street Journal, 18 December 2013, accessed October 2018
- Graham Mackay resigns from Reckitt Benckiser board, Post Online Media, 13 June 2013, accessed January 2019