The favourites took control early on and were rewarded when Ireland U18 Schools centre Rory O’Loughlin broke through two tackles for a try in the 18th minute. Fly-half Ross Byrne converted.
Kilkenny, led by Michael Triggs, Sam Sterling and Ross Deacon, battled bravely to instigate a comeback but Byrne extended the St Michael’s lead to 10 points with a 33rd-minute penalty.
Kilkenny’s efforts were rewarded with a penalty following sustained pressure and Simon Williams’ kick left seven between the sides (10-3) at the interval.
St Michael’s were rocked by the loss of O’Loughlin through injury and his departure spurred Kilkenny on.
But there was simply no way through the winner’s defence. Byrne nailed his second penalty in the 63rd minute to restore their 10-point advantage which they maintained until the final whistle.
Scorers for St Michael’s College R O’Loughlin try; R Byrne 2 pens, con.
Scorers for Kilkenny College S Williams pen.
ST MICHAEL’S: C Diamond; C Fagan, R O’Loughlin, R Kavanagh, A Leavy; R Byrne, B Holland; A Barr, G Kelly, J Lawless, R Molony, A Coleman, J Murphy, D Leavy (c), D Lawlor.
Replacements: N McCarthy for O’Loughlin (38); D Coulson for Barr, S Harold for Coleman, (both 42); C Kelleher for A Leavy (58); A Penny for Murphy (64); C Duffy for Lawlor (67); B McDermott for Kavanagh (74).
KILKENNY: J Duncan; T Bulfin, S Sterling, R Bailey-Kearney, S Williams; B Ridgeway, D Leybourne; G Condell, R Foot, S Delahunt (c), J Moynan, J Holland-Brennan, H Crowley, M Triggs, R Deacon.
Replacements: E Kelly for Ridgeway (54); H Thomas for Duncan (56); C Miller for Leybourne (62); J Baker for Condell (69); G Mullins for Holland-Brennan (72).
Referee: S Gallagher, Leinster Branch.