Mayo, who has led the business network since 2009, will succeed Gillian Murray, who is stepping down after 14 years at Pilotlight, the past seven as chief executive.
Before joining Co-operatives UK, Mayo was chief executive of the think tank the New Economics Foundation. He previously held the same role at the National Consumer Council.
Bruce McCombie, head of partnerships at Pilotlight, will act as interim chief executive from when Murray leaves in April to when Mayo joins in the summer.
Murray is taking some time out to consider her next move.
Sally Bailey, chair of Pilotlight, which connects businesses and charities to make them both more effective, said: “Ed will help Pilotlight accelerate its mission to help make a difference to those who need it most.”
Mayo said: “No one makes more of a difference to communities than the voluntary sector, yet small charities at the heart of this are under more stress than ever.
"I look forward to working with the individual and business members, the trustees and the staff team of Pilotlight, who together make up an extraordinary community of purpose."