20-year-old Mr Mullally from Innishannon went missing following a night out with friends in Cork city on 14 December.
Since then, search teams, including garda and Naval Service divers, and Mr Mullally's family and friends have been searching the River Lee and Cork Harbour.
One of the search teams discovered the body of a man washed up on the shoreline at Tivoli Docks just before 10am today. It has been confirmed as the body of Mr Mullally.
A post mortem examination will be carried out on the body later.
Gardaí are not treating his death as suspicious.
