Mr Mills is currently the FCA’s director of competition and will add the strategy brief to his role.
He will become a member of the FCA’s executive committee.
He joined the FCA in September 2018 from the Competition and Markets Authority, where he was senior director for mergers and state aid. He also worked at the Office of Fair Trading.
He is a qualified solicitor and, before joining the OFT, practiced competition and anti-trust law at City firms SJ Berwin, Jones Day and K&L Gates. He is a trustee at Stonewall, the LGBT+ support and advocacy charity. He was born in Cardiff.
At the FCA he has led the regulator’s work to make sure competition works well for consumers and has helped tackle anti-competitive behaviour in the financial services sector.
Mr Mills said: “I am delighted to be stepping up to lead the FCA’s Strategy and Competition division.
“The FCA’s work makes a real difference to the everyday lives of people across the UK. I’m committed to continuing that crucial work in developing robust policy, promoting competition and encouraging innovation.”
Christopher Woolard, incoming interim chief executive, said: “Sheldon has extensive experience and a proven track record in regulation and competition policy and law.
“Since joining the FCA he has been an inspirational leader and shown his ability to deliver large, complex projects. His appointment will ensure the FCA continues to deliver for consumers.”
Mr Mills will take up his role on 16 March.