Keller was previously head of customer insights for T-Mobile UK. He has also worked at Air Miles as head of customer relationship management.
His task at Capital will be to lead a team covering research, programming strategy, community relations, charities and customer relationship management.
Keller's team will be responsible for delivering programming strategies and commercial strategies that will drive revenue and increase listeners' loyalty. They will look at platforms including digital, texting, live events and CDs.
Capital said that it has appointed Keller because it is facing strong competition from multimedia content offered through other platforms, as well as rival radio companies.
Keller said: "Capital Radio already possesses a relationship with its listeners that would be the envy of most FMCG brands. The opportunity to run an insights department within a radio company with this relationship and a proven commitment to its listeners is one I couldn't pass up."
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