General Michael Collins died 91 years ago, on August 22, 1922.
The site of the memorial is the location of the iconic photo of Collins walking through the barracks with a young civilian piper, Alphonsus Culloten, behind him.
The picture was taken as he returned from a memorial service on August 7, 1922, just two weeks before he was fatally wounded in Cork.
Private Noel O'Donnell, the barracks' barber, researched the background to the photo with the assistance of the engineering section and military archives of the barracks.
The exact location of the image was determined as the site for the memorial which was financed and paid for by the soldiers of Cathal Brugha Barracks.
"I wish to commend the men and women of Cathal Brugha Barracks on proposing and establishing such an appropriate and fitting memorial to our first commander in chief," Lt Gen O'Boyle said.
"It re-affirms the Defence Forces' enduring loyalty and commitment to the memory of General Michael Collins and this memorial is very much a tangible example of that," he added.