Cannon, who joined S&N-owned Scottish Courage in 1996, takes over from Jeremy Blood, who has been promoted to MD of S&N Pub Enterprises, the leased pub company of Scottish Courage.
Cannon is a former director of the Benevolent Society, a drinks industry body in Scotland, and previously spent nine years at Tesco, latterly as head of customer services. Her new role focuses mainly on group-level communications with investors.
S&N is one of Europe's biggest brewers and makes John Smith's bitter and Strongbow cider in the UK.
It also owns Russia's biggest-selling beer, Baltika, through its Baltic Beverages Holding joint venture with Carlsberg.