A first-half blitz in which St Gerald's College scored 2-5 provided the platform for the Castlebar side to advance to the final.
However, St Colman's from Claremorris came storming back and were left to rue 10 costly wides and the concession of two soft goals.
St Gerald's first goal came on seven minutes when Michael Plunkett knocked the ball from the goalkeeper's hands, while the second was a gift in which Adam Murphy blasted home after 23 minutes.
St Colman's managed just a single point for the opening 28 minutes, that coming on 15 minutes from Kevin Lynch.
With James Durcan scoring three superb points, two late points from Lynch kept his side clinging on at the break – 2-5 to 0-3.
The gap was narrowed to four, but Durcan again popped a big score on 54 minutes – the first of only two points St Gerald's managed after half-time. St Colman's then came within three, leaving them searching for a goal in stoppage time before Plunkett made the game safe with a late point.
SCORERS – St Gerald's: M Plunkett 1-1, J Durcan 0-4, A Murphy 1-0, P Durcan and K Egan 0-1 each. St Colman's: A Gallagher (4f) and K Lynch (1f) 0-4 each, T Waldron 0-1.
St Gerald's – D McHale; K McNally, M McHugh, K Egan; P Durcan, M Hall, C Dravins; R Coleman, E Rogan; J Gannon, M Plunkett, S Conlon; R Carolan, A Murphy, J Durcan. Subs: J Lydon for Carolan (45), M Ruane for Gannon (50).
St Colman's – D Boyle; S Brennan, K Jordan, C Finn; R Finn, C Higgins, A Costello; S Coen, S Waldron; T Waldron, A Gallagher, A Peters; L Noone, K Lynch, B Walsh. Sub: D Kelly for Waldron (52, inj).
Ref – D Hunt (Roscommon)