Newcastle West looked set for a fourth title when Paul Hannan kicked them 1-10 to 1-9 ahead in the first of four minutes of injury time.
But Adare, who had led for most of the game, went straight up field and Jack English blasted high to the net to set the men in red and black on their way to a historic win.
Two years ago Adare were relegated from the senior ranks but bounced straight back with the 2016 intermediate title. That side went all the way to the Munster final, losing to Kenmare Shamrocks.
Adare made many stand up and take notice with a quarter-final replay win over Ballylanders and then a semi-final victory over Dromcollogher-Broadford.
Still this young side were underdogs in the final against 2015 winners Newcastle West.
But they showed no lack of maturity to lift the title and see them advance into the Munster championship against Nemo Rangers.
Adare were 1-6 to 0-6 ahead at half time. Newcastle West were 0-6 to 0-3 clear by the mid-point of the half with Jamie Lee, Stephen Kelly and Iain Corbett kicking points.
But Newcastle West then failed to score for the final 16 minutes of the half as Adare got on top.
Crucial was a 17th minute goal from Hugh Bourke and his point that followed to move Adare 1-4 to 0-6 ahead.
Robbie Bourke had the final two points of the half for the eventual winners.
Just six minutes into the second half the final was level when Iain Corbett goaled.
Back came Adare with two fine points from Mikey Lyons to lead 1-9 to 1-6 with 10 minutes to play.
Newcastle West rallied and Lee, Corbett and Michael Quilligan points tied up the contest for a fifth time, 1-9 each.
In the first minute of injury time, Hannan kicked Newcastle West ahead for the first time since the 14th minute.
Adare weren’t done and Jack English goaled within 60 seconds and Charlie McCarthy put the seal on the win with the final kick of the final.
H Bourke (1-5, 3f), J English (1-0), R Bourke (0-2, 1f), M Lyons (0-2), C McCarthy (0-1).
I Corbett (1-2), J Lee (0-4, 1f), S Kelly (0-1), T Quilligan (0-1f), M Quilligan (0-1), P Hannan (0-1).
J Hickey; O Collins, A O’Connor, E Costello; E Ryan, D Connolly, P Maher; S Doherty, S Keeley; N Mulvihill, J English, M Lyons; M Connolly, R Bourke, H Bourke.
S O’Connor for E Costello (40), A O’Connell for P Maher (54), C McCarthy for M Lyons (62).
A Ruddle; M O’Leary, B O’Sullivan, S Browne; M O’Leary, S Nix, P Hannan; M McMahon, I Corbett; S Kelly, J Kelly, S Murphy; T Quilligan, C Sheehan, J Lee.
AJ O’Connor for T Quilligan (37), D Woods for S Murphy (37), E Murphy for B O’Sullivan (45), M Quilligan for S Kelly (49), E Hurley for M McMahon (57).
J Murphy (Ballylanders).