The life-long Aston Villa fan has always taken a close interest in the workings of the club and is the second high profile appointment since the turn of the New Year.
King joins the board after former KPMG chief Steven Hollis was named as the new chairman of the club last month.
Hollis said: "I was delighted when Mervyn agreed to join the board. His dedicated support for the club is well known.
"Mervyn successfully steered the Bank of England through the most turbulent economic headwinds in living memory and his appointment to the board is a huge boost as we plan our path back to more successful times."
King added: "It is a privilege to be asked to serve as a director of this great club. I watched my first match at Villa Park more than 55 years ago, and have experienced the highs and the lows since then.
"I shall do my best to help the rebuilding of Aston Villa Football Club as together we return it to its position as one of the top clubs in the world."