Ardscoil have won four of the last seven Harty Cups on offer and are now targeting All-Ireland glory, with Connacht champions Presentation College Athenry next up in the last four on Saturday.
Ardscoil had to dig this one out as Leinster runners-up Kilkenny CBS, who trailed by six points in the first half, were back to within a single point after half-time, 1-8 to 1-9 adrift.
But two goals in three minutes secured victory for Ardscoil, as Conor Boylan netted in the 40th minute before Paraic O’Loughlin scored his second goal two minutes later.
Twice before full-time, Ardscoil led by nine points before clinching an eight-point win.
Ardscoil led by five points at half-time, 1-9 to 0-7, with Peter Casey warming up nicely for his All-Ireland senior club final appearance with Na Piarsaigh.
The 2015 All-Ireland U21 medallist with Limerick struck four brilliant points in the first half and Ardscoil had the ideal start when they scored a fortuitous goal in the very first minute.
O’Loughlin’s effort from the left touchline wasn’t dealt with by Kilkenny CBS goalkeeper Liam Dunphy and the green flag went up to signal the opening score of the game.
CBS scored their only goal in the first minute of the second half and this was another scruffy effort as Bill Sheehan scrambled the ball home from close range after Sean Bolger’s speculative effort caused havoc in the Ardscoil goalmouth.
P O’Loughlin 2-0, P Casey & P O’Brien (3f, 1 65) 0-5 each, C Boylan 1-1, D Carroll & D Fitzgerald 0-2 each.
S Bolger 0-6 (2f, 1 65), B Sheehan 1-1, N Brassil 0-2, S Mahony, J McEvoy, J Molloy & R Buckley 0-1 each.
E Foley; S Hogan, S Phelan, R Connolly; C Houlihan, N Fox, J Boylan; J Flynn, B Ryan; D Carroll, P Casey, P O’Loughlin; C Boylan, P O’Brien, D Fitzgerald.
J Delahunty for Connolly (40), J McInerney for O’Loughlin (50), J Gleeson for Flynn (52), D Cunningham for Casey (55), I Considine for Ryan (55).
L Dunphy; K Ryan, C Flynn, C Fitzpatrick; S Mahony, M Drennan, C Doheny; C Kavanagh, N Brassil; S Bolger, J Leahy, J McEvoy; B Sheehan, C Heary, J Molloy.
C Drennan for Heary (38), R Buckley for Brassil (59), S Boyd for McEvoy (59), D Dunne for Flynn (60+3).
Fergal Horgan (Tipperary).