She is currently the boss of Scottish charity Cornerstone, which provides a range of services to people with learning disabilities, physical disabilities, autism and dementia.
Harris has a wide range of experience and notable achievements including being a former director of the Aberdeen Football Club Community Trust, the former chair of the Scottish Government’s Social Investment Fund, a board member of the Robertson Trust and Scottish EY Entrepreneur of the Year, in 2017.
She said: “I am very sorry to leave all my great friends and colleagues at Cornerstone. Over the last 11 years I have worked with some amazing, committed people who have shown courage and passion despite what, at times, has been a challenging time for the social care sector in Scotland.
“Mencap is a very well-known and respected charity and I am excited about the opportunities that lie ahead.”
Derek Lewis, chair of Royal Mencap Society, added: “As we embark on the next phase of our ambitious development strategy, we look forward to Edel’s leadership and commitment to people with learning disabilities.
“Her experience and insights will be invaluable, especially those from her 11 years as chief executive of Cornerstone,” he added.