In the early decades of the 20th century, the local curate, Fr J. J. Kearney popularised hurling and football amongst the town's youth.

[3] In the 1920s, a young hurler called Matt Walsh helped the club win its first senior hurling title in 1928.

He became Fr Matt Walsh and retained remained involved with the sport even though he spent most of his life on religious missions in Nigeria.

On a trip home in 1960, he trained the senior hurling team that was pipped by a point by Borris-in-Ossory in the county final.

This happened in Inchicore when the Laois representatives defeated Bray Emmets GAA and then accounted for Louth champions, Newtown Blues in the final.

The All-Ireland final was fixed for the following Sunday and the Laois and Leinster champions were unable to muster the same line-out because of the restricted travel services of the period.

In the Leinster final against Athlone, Portlaoise found themselves eleven points adrift with only twenty minutes remaining.

[2] Portlaoise, by winning its 35th county football title in 2019, moved to top of the honours list in Laois.

[6] The record of the hurlers is headlined by two appearances in Leinster club finals in the 1980s and 1990s and a four-in-a-row of county title wins from 1981 to 1984.

[7] The following year, having gone back to junior ranks the ladies were beaten in the semi-final of the championship but in 1991 the club won its third title defeating Crettyard 2–5 to 1–5.

Portlaoise were to win their first Laois Ladies' Senior Football Club Championship title in 2020 when they defeated reigning champions Sarsfields who were going for nine-in-a-row on a scoreline of 1–12 to 0–12.

[12] Portlaoise won their first adult level trophy defeating O'Moore's on a scoreline of 3–12 to 1–04 to win the 2020 Laois Junior Camogie Championship.

Portlaoise backed this win up with their successful defence of the trophy in 2021 defeating Camross Camogie 1–15 to 2–05 in O'Moore Park on 20 November 2021.

[citation needed] In 1953, the club merged with two other local teams, The Rovers[15] and Kilminchy,[16] forming a unified organisation.

Long-serving secretaries included Jim Loughlin, Jimmy Cotter and Bill Phelan, while Dick Sides was treasurer for nearly thirty years.

[17] As of 2025, Portlaoise have "split" the role of chairperson into a joint position shared by Eamon Fennelly and Dermot Costelloe.

[39] In 2009, Portlaoise recorded a rare double, winning Division 3, Féile Péile na nÓg in Kildare, when they defeated Limerick club, Monaleen GAA, 5-4 to 0-3 in the final in St. Conleth's Park, Newbridge and Division 2, Féile na nGael at home in Laois/Offaly, beating St Patrick's, Portaferry GAA from Down, 4-6 to 1-4.

In the summer of 1985, Critchley played one of his best ever games against Wexford in the Leinster championship and Laois reached the provincial final for the first time in 36 years.

Playing at wing back, he made the breakthrough (alongside his brother Gerry) on to a Portlaoise club team in the mid 1970s.

Three years earlier, he had been player-manager when Portlaoise won the All-Ireland Club Football Championship title.

[44] Two Portlaoise players were also selected to the Laois Hurling Team of the Millennium, with John Taylor at left half back, and Pat Critchley at midfield.