​The club was formed in 1904 when local parish rivals, Ballymoyer Emmetts and Tullywinney Sarsfields, came together to form a team at Whitecross which is the centre of the parish of Loughgilly, in south Armagh. We had not long to wait for our first success on the field when in January, 1906 we travelled to Abbey Park, Armagh, to take on the local Armagh Young Irelands (now known as Armagh Harps) - in the final of the county football championship. The newly formed St Killian's emerged victorious by a goal on a scoreline of 2-4 to 1-4. This was to be their only success in the senior championship.

In 1935 was our next championship success when we annexed the Junior title by defeating near neighbours, Clady, in the final. Six years later in 1941 we defeated the famed Clan na Gael from Lurgan to win the Junior title for a second time. The opponents included within their ranks two Ulster and county stars in Eddie McLoughlin and a future President of the Association, Alf Murray.

Whitecross had their next victory in 1969 in the Junior Championship when we defeated Ballymacnab by two points 0-4 to 0-2 in the final at the Athletic Grounds, Armagh. Nine years later (1978) they won the Intermediate Championship defeating Cullaville Blues after a replay which took place at Carrickcruppen.

Another highlight of 1978 and indeed in the history of the club was the official opening of St Killian's' very own football pitch - Pairc Naomh Cillian - which was opened by Con Short, the then President of the Ulster Council of the GAA. Armagh played Down in the opening match and afterwards both teams, guests and friends were entertained in the Ardmore Hotel, Newry.

The Club had its new hall and changing room complex opened by GAA President Jack Boothman, on 4 November 1995, and a club history was launched at the Annual Dinner in their new premises during February 1996.

Whitecross were beaten in the 1995 Junior Football Championship Final by Ballyhegan in what became known as one of the best finals at any grade in Armagh football for several decades. They reached the final again in 1996.

The St Killian's Senior team won promotion from the 2nd Division in 2005 and successfully fought off relegation in 2006. In 2007 the team was relegated back to Division 2, but won the Intermediate Championship.

Whitecross gained promotion to the Senior League (Division 1) in 2008 and stayed in this division until 2014 when they were relegated to the Intermediate section of the league.

In 2015 Whitecross reached the County Intermediate Championship Final, we played Clann Eireann in the Armagh Athletic Grounds, we were defeated 2-13 to 2-8.