Eccleston will assume the role on Nov. 3.
The company says Eccleston has more than 30 years of experience in capital markets, information services and financial sectors. He was most recently the president of S&P Capital IQ and chairman of the Dow Jones Indices. He also worked at Thomson Financial and was a long-time executive at Bloomberg LP.
Eccleston is taking over the top job from Thomas Kloet, who will remain CEO until Oct. 31.
Kloet had joined the TMX Group in 2008, shortly after its merger with the Montreal Exchange and as the industry headed into a period of consolidation.
The TMX Group owns the Toronto Stock Exchange, the TSX Venture Exchange, the Montreal derivatives market and others. For the past year, the TMX has been focused on expanding its services as it struggles to attract more companies to list on its main exchange.