Hollinshead announced in August that he was to step down from his role at Trinity Mirror after 17 years at the publisher to become Group CEO at Nova International, the events and sports marketing company.
Dentsu Aegis Network’s activity outside of London include Carat, iProspect, Vizeum, Amplifi and Amnet operations in Manchester, Edinburgh, Leeds and Newcastle.
Dave Lucas, managing partner at Dentsu Aegis Network, said of the appointment: "Mark’s experience, know-how and capabilities will be a tremendous addition to our management team, as we continue to grow our regional businesses, and build out a best in class content proposition. The opportunities to welcome somebody with Mark’s pedigree to your team are few and far between"
Hollinshead added: "This is an exciting time to be joining Dentsu Aegis Network and I'm really looking forward to working with what I know to be a highly talented team to add real value where I can."
He will take up his role within the marketing services group in October.