Mark Hollinshead was chief operating officer of Trinity Mirror between 2012 and 2015, having previously been an MD in the business, and of its Media Scotland business.
He has also worked at the News Media Alliance, the Great Run Company (which organises the Great North Run and other events) and been a non-executive director of Dentsu Aegis Network.
Hollicom launches with a team of eight, including 20-year industry veteran Gaynor Simpson. Hollicom's co-founder and CFO is Steven Simpson, a former PwC partner who first met Hollinshead at university.
Trinity Mirror has turned to the agency for advice on the strategy of its regional newspapers division, it has been confirmed.
Hollinshead, who takes the role of CEO, said: "Our job is to enhance and protect the reputations of our clients and help deliver their business objectives, both strategic and financial. We will achieve this by immersing ourselves in the strategy of our clients and then by telling their stories in a compelling and impactful way."
The agency will officially launch on 1 June with a party which a press release says "will be backed by Hollicom supporters Jack Daniel’s and OK! Magazine". Asked by PRWeek whether the two brands were clients, a spokeswoman for the agency said that they were not, but that some clients would be confirmed in the near future.