Whitty converted his side’s seventh spot-kick, then saved the eighth St Patrick’s attempt by Dara McVeety before Conor Whittle slotted home the decisive penalty.
The stopper had kept De La Salle’s silverware hopes alive earlier in the second period of extra-time by producing a superb save to deny a header from Saints’ substitute Jonathan Leddy.
In the first-half DLS’s Conor Coad was foiled by goalkeeper Joe Masterson before Chris Kervick and Kevin Flynn both missed gilt-edged chances. That profligacy would nearly cost them in the second-half as Craig Murphy was inches wide with an acrobatic overhead kick on 53 minutes. Still, De la Salle persevered and despite Flynn missing another chance in the last minute, Whitty ensured they became the first Waterford team to claim the title.
J Masterson; A Graham, P Graham, C Higgins (B Kiernan, 70), R O’Reilly, D Talbot, K Devine (V Coyle, 76), C Bogue, D McVeety, C Murphy, K Johnston (J Leddy, ht).
S Whitty; M McManus, G O’Donovan, A Potter (capt), P Fitzgerald, C Morris (D O’Leary, 76), C Whittle, C Kervick (E Kindlan, 86), A Galibert, C Coad, K Flynn (J Hale, 103).
Referee: Richard Glynn (Dublin).