A dominant first-half display helped Castleknock claim the title at Parnell Park. The Dublin club took control of affairs at midfield through the impressive Shane Boland, with Rory Corcoran kicking four first-half frees to reflect his side's territorial dominance.
Three further points arrived before the interval, two from the influential Jamie Tunney, as Castleknock entered the break with a healthy 0-7 to 0-1 advantage.
A point from Donal Shanley within seconds of the restart offered the Wexford club a modicum of hope, but Corcoran kicked a fine score in reply to stall any St Fintan's momentum.
The turning point arrived soon after, with Alex Griffith producing an exceptional save to deny Joey Wadding after the usually impeccable Graham Hannigan had lost possession close to goal.
In the 38th minute, the contest was effectively settled as Corcoran put the finishing touches to a wonderful team move, firing home from 10 yards after being fed by the impressive Thomas Shields.
Try as they might, there was no way back for Fintan's, who managed a consolation goal from substitute Niall Moore and a disappointing day for them was compounded by the late dismissal of Paddy Keane after a second bookable offence.
Scorers – Castleknock: R Corcoran 1-5 (0-4f), J Tunney 0-2, T Corcoran, D Carlos, S Boland 0-1 each. St Fintan's: N Moore 1-0, D Shanley (2f), C O'Brien ('45', f) 0-2 each, T Power 0-1f.
Castleknock – A Griffith; J King, G Hannigan, P Mulvihill; T Quinn, T Shields, V Turner; S Boland, J Tunney; D Curran, C Daly, M Griffin; T Corcoran, R Corcoran, D Carlos. Subs: C Neville for Quinn (19), S Lynch for Griffin (h-t), Griffin for Lynch (58).
St Fintan's – P McDonnell; E Whitmore, F Staples, J Staples; B Hughes, K Day, J Rossiter; J Rowe, P Doyle; C Day, C Sinnott, D Shanley; J Wadding, P Keane, C O'Brien. Subs: N Moore for Day(39), T Power for Rowe (39), B Lacey for Turner (43), D Kelleher for Shanley (45), A Murphy for Rossiter (55).
Ref – J Hickey (Carlow).