The current Northern Irish journalist of the year, Mike has edited the Bel Tel for the past five years.
Now he is moving back to the mainland as group editor of Newsquest Sussex and editor of The Argus.
He joins The Argus in succession to Michael Beard, who left at the end of last month to take up a PR role with Public Health England.
The paper has seen some of the biggest circulation declines in the industry over recent years, with the average daily sale now down to 14,370 according to the most recent ABC figures.
Said Mike: “I am tremendously excited about taking on the opportunity in Brighton. It is a fantastically dynamic place and the newspaper and digital platforms under me will reflect that.
“We will be challenging when we need to be and supportive at other times. We will be at the centre of debate and, at the core of everything; our journalism will be vital and trustworthy.
“I have a track record at producing compelling newspapers and websites. This will continue.”
Under Mike, the Bel Tel was named UK Regional Newspaper of the Year in 2011 and has been named Northern Irish Newspaper of the Year in four out of the last five years.
Managing director of Newsquest Sussex Dawn Sweeney said: “I am delighted to welcome Mike to The Argus.
“He is an experienced Editor with an outstanding pedigree and I look forward to working with him in the New Year to further develop The Argus print and online platforms.”