Although an unfashionable second-tier club, Llwynypia provided several international caps around the turn of the century as the 'Rhondda forward' gained acceptability into the Welsh pack.
Alexander as a strong prop forward was first selected to represent Wales in the 1898 Home Nations Championship in a game against Ireland, under the captaincy of Billy Bancroft.
After a strong Welsh win, Alexander retained his position for the last game of the campaign against England.
Alexander was back for all three matches of the 1899 Championship, which saw Wales demolish England in the opening game at St Helens, but then slip away in the later two encounters against Scotland and Ireland.
The match is noted as a transition game which saw the end of an older generation, with not only Alexander but also Bancroft playing his last game, and the introduction of future Welsh heroes Rhys Gabe, Dicky Owen and Dick Jones.