The Irish-born 23-year-old joins Ryan Hedges (Barnsley), Ash Taylor (Northampton Town), Curtis Main (Motherwell) and Craig Bryson (Derby County) at Pittodrie for the coming season.
Dons boss Derek McInnes told the club website: "Jon is a young, developing talent who we’re pleased to have as part of the squad for this season.
“He offers cover on the right side but also played in a more advanced role in college football for Bobby Clark and his successful Notre Dame side and scored some impressive goals."
