In July 2015 the Football Association of Ireland announced the formation of the club as an expansion team for the upcoming 2015–16 Women's National League season. The club played its first match on 19 July 2015, hosting Celtic at Buckley Park. Ahead of the first WNL season experienced campaigner Sylvia Gee was signed, to add experience to a youthful squad. In game week 8 of the 2015-16 season Kilkenny United recorded their first ever draw and put their first ever point on the table. They drew 1-1 with Cork City W.F.C.. There was a few close games for Kilkenny in their first ever season in the league but it wasn't to be for Kilkenny as they ended the campaign with 1 point on the board.
2016
Kilkenny recorded their first win in the 2016 season when they were drawn against in the quarter finals of the FAI Women's Senior Cup. Kilkenny came out 3-1 winners with goals from, Jenny O'Keeffe, Niamh Kelly and Hannah Scott. Kilkenny United commenced to the semi finals of the cup but lost out to a strong Wexford Youths W.F.C. in the semi finals. The 2016 League campaign didn't go as planned for Kilkenny with the club failing to pick up any points throughout the season. Although the club didn't manage to get any points on the board it was a great learning experience for a young Kilkenny squad.
2017
The 2017 season didn't start as planned as Kilkenny went through numerous managers before finally getting the right man for the job on June 20, 2017. Kilkenny United appointed Casey McQuillan who had much experience in the league from previously managing Shelbourne L.F.C. and Raheny United FC. On July 9, 2017, history was made for Kilkenny in Thomastown when Kilkenny won their first ever game in the Women's National League. They beat Galway W.F.C 1-0 which was a very historic day for the club. The Kilkenny goal came from Leanne Tumelty. Kilkenny United ended the season with the single 3 points and single win on the board. It was a very progressive season for the club on and off the field. Kilkenny also recorded a win in the quarter finals of the FAI Women's Senior Cup when they beat TEK United 3:1. Kilkenny's goals were scored by Jennifer Chambers and Sylvia Gee. Kilkenny were drawn against UCD Waves in the Semi Finals of the cup but Kilkenny sadly slipped at the last hurdle and lost out on a trip to the AVIVA.
2018
At the start of the 2018 season Casey McQuillan stepped down as manager of the club. Kilkenny signed many new experienced players including Carla McMannus who is an ex Ireland Women's Under 17s player. Kilkenny also kept players with great experience at the club including Nicole Plunkett, Niamh Kelly and Bronagh Kane to name a few. Kilkenny started off the 2018 season at debutantes Limerick WFC and lost out to a strong limerick side on the day. The club introduced an Under 16 squad which was entered into the Kilkenny & District League On July 12th 2018 Kilkenny United announced a link up with Real Football academy Swans. They announced their intention to set up a pathway to the Women's National League for the Real FA Swans players.
