By now there were many changes to the social and sporting order after the trauma of the wars in Europe and at home. The new independent government of Ireland was in place and the old establishment structures were being dismantled. On the club scene a number of notable clubs did not survive; Cork County and Lansdowne (Limerick) did not re-appear. Newcomers to senior ranks included Young Munster, Limerick Bohemian, Dolphin and Sunday’s Well.

Dolphin had an early Munster Senior Cup success beating a strong Constitution team 5-0 in the 1921 final at the Mardyke. However Constitution, re-organised under the captaincy of P.A.McGrath, were back on top in 1922 and 1923 with two final wins over Garryowen. Constitution were nominated as Munster’s representative for the newly inaugurated Bateman Cup between the four Provincial Cup winners, though the Cup final had yet to be played. Constitution had reached the final, but delays prevented the other finalist being decided, so the Munster Branch awarded the Cup to Constitution. Thus they played in the Bateman Cup, but lost to Instonians in the semi final. Subsequently, Constitution agreed to play Garryowen in the Munster Cup final and won a heroic victory 8-0 at the Mardyke. Ivan Popham won four International caps in 1921-22 season.

H.L.Tivy stood down from Presidency in 1923 having steered the club as its main patron since its inception. The newspaper from which the club had its origins was also a victim of the new nationalist climate and ceased publication.

Constitution reached the Munster Senior Cup final in 1928 with wins over UCC and Garryowen, but lost in the final 0-6 to Young Munster. This was the famous Young Munster side that went on to win the Bateman Cup. Constitution turned the tables the following year when the teams met again. Constitution, captained by Matty Murphy, won 5-0 at the Mardyke. Matty, nicknamed ‘the Prince’, was the first of the noted family to taste success with the club. His cousin Noel was also a member of the team and was capped for Ireland against England in 1930.

R.M.Magrath had become President Munster Branch in 1920 and was further honoured as President IRFU in 1921-22. David Desmond, the first Munster Senior Cup captain, was President Munster Branch in 1927-28.