Robertson, who will be assisted by Grant McCann, ended last season in charge at the ABAX Stadium after taking over from Darren Ferguson in February.
Chairman Darragh McAnthony said in a statement on the club’s website: “I am delighted to finally announce that David Robertson is our new first team manager with Grant McCann joining him as assistant manager.
“They have both signed three-year deals which I have no doubt will lead to three of the most successful years since I have become chairman of the football club.
“The recruitment process was a long one that I embarked on back at the start of May, one I took my time with and analysed from top to bottom over the last couple of weeks.
“It involved me speaking to four other candidates extensively as well as our new management team.
“I of course took into account the 14 games they were in charge for and the work they have put in since day one and allowed them to present their vision for the future of the football club and their goals on and off the pitch.
“The new management team are well aware I yearn for winning a title, yearn for healthy cup runs, yearn for goals galore and ultimately to be entertained with the style of football we play.
“The club has invested nearly £200,000 in a new pitch for the upcoming season, one I’m told will be up there with the best of them and with our recruitment process well under way, I have no doubt success will follow and next season could and should indeed be one of our best yet.”