The agency has signed up F-H associate director Ben Thornton, just weeks after the appointment of Oliver Pauley - also from F-H.
Thornton makes the switch in June, taking the role of associate director, after seven years at F-H. He will report to former colleague Pauley, who recently joined as a partner.
Portland's public affairs clients include Coca-Cola, McDonald's, Anheuser-Busch InBev, Apple, Google, Vodafone and Virgin Media. The agency recently added BAE Systems, taking the account from Bell Pottinger Public Affairs.