Sandra Hobson, the agency's head of London, has been promoted to board director. Ellie St George-Yorke has been promoted to head of Leeds, and Rosanna Head joins the agency as associate director in London.
Head has in-house and agency experience, including John Lewis, Nestlé Purina and Hill+Knowlton. She will work closely with Hobson to launch the agency's new reputation and issues management offering in the food and drink sector.
Louise Vaughan, managing director at Definition, said: "The past six months have seen Definition land several major new international and UK clients, which is a testament to the outstanding work the team produces."
Vaughan added that the new hires demonstrated the agency’s commitment to growing its client base both in and outside of London.
The agency secured a number of new business wins over the summer including national healthcare provider Benenden Health, broadband wholesaler TalkTalk’s FibreNation, and an event management business based at The Mansion in Leeds' Roundhay Park.
Louise Watson-Dowell has also been promoted to the newly created role of digital account director, responsible for the roll-out of Definition’s growing digital communications offer, which includes a range of LinkedIn training and promoted content products for clients.
Vaughan added: "The new role is part of our ambition to provide clients with new and evolving communications programmes."