The newly formed club has appointed the former Cork City boss as manager ahead of the 2014 season in the Airtricity First Division
In a statement released by the club, Dunne is described as "the right person" to bring the club forward as they prepare for life in the Airtricity First Division in 2014.
The statement read: "Tommy's managerial success with Cork from start-up and working with a tight budget coupled with his ambition, energy and enthusiasm matched our vision for the club and without doubt makes him the right person to bring Galway Football Club forward.
"We are extremely fortunate to have someone of the calibre and experience of Tommy accept the position to lead Galway Football Club on its journey into League of Ireland football and are genuinely excited by the challenges that lie ahead for all Galwegians."
Dunne had most recently served as manager of Airtricity Premier Division side Cork City, where he guided the Leesiders to promotion from the First Division in 2011 before parting company with the club in August 2013.
The 41-year-old will be officially unveiled as manager during the launch of the club on Monday December 2 at the Connacht Hotel in Galway.
Galway will compete in the 2014 Airtricity First Division after a report commissioned by the Football Association of Ireland (FAI) recommended the establishment of a single senior football club in the region.