He founded Harwood Capital Management in 2011, a successor to its former parent company JO Hambro. He is currently the chief executive officer and investment manager of UK investment trust North Atlantic Smaller Companies.
Mills also serves as non-executive director of companies including AssetCo, MJ Gleeson and Oryx International Growth fund.
Hipgnosis appoints former Round Hill chair
The trust said Mills intends to donate his director fees received from the company to the Harwood Charitable Trust, which provides educational support, mainly for doctors in Africa.
Mills' appointment follows the ousting of Hipgnosis Songs chair Andrew Sutch and non-executive directors Andrew Wilkinson and Paul Burger at the trust's annual general meeting held in October, when shareholders voted against their reappointments.
In early November, Robert Naylor, the former chair of the fellow music royalties trust Round Hill Music, was appointed chair and a non-executive director, while Francis Keeling was named non-executive director.
Hipgnosis catalogue sale cancelled as shareholders vote against continuation
In today's (15 December) announcement, Hipgnosis Songs said it has appointed a number of non-executive directors as chairs of committees.
Cindy Rampersaud will serve as chair of the audit and risk management committee, Robert Naylor as chair of the nomination committee, Simon Holden as chair of the portfolio committee and Francis Keeling as chair of the management engagement committee.