Aaron began his LOI career with Galway United in 2009, making his debut against Shamrock Rovers in a game where Stephen Bradley scored the winning goal in a 1-0 win for Rovers.
The following season Aaron signed for Bohemians where he played in and won the Setanta Cup final against St Patrick’s Athletic at Tallaght Stadium. He then moved to Sligo Rovers for the 2011 season where he won the FAI Cup against Shelbourne.
Aaron returned to Dublin and signed for the Hoops ahead of the 2012 season. He scored the winning goal as Rovers won the Leinster Senior Cup that year against St. Patrick’s CY. He then returned to Sligo Rovers ahead of the 2013 season and won the FAI Cup against Drogheda United. The following May he won the Setanta Cup as Sligo overcame Dundalk. That summer, he moved back to Dublin and signed for St. Patrick’s Athletic and won the FAI Cup and Leinster Senior Cup. The following year he won the EA Sports Cup with Pat’s as they overcame Galway. He then made the decision to sign for Limerick in the First Division in February 2016 and scored 11 goals as Limerick won the title and won promotion. He signed for Harry Kenny’s Bray Wanderers ahead of 2017.
Halfway through 2018, he re-signed for Rovers. In 2019 he scored 15 goals in all competitions and won the FAI Cup as Rovers overcame Dundalk. One of the goals was a 25-yard screamer in the Europa League against Apollon Limassol.