Waterford finished strongly to defeat Cork by 4-19 to 0-20 in a pulsating Croke Park clash.
Victory means Na Deise will lock horns with Galway in a novel decider in three weeks but they may well go into that game without both Conor and Austin Gleeson.
Hurler of the Year Austin should have been sent off for pulling off Luke Meade's helmet in the 18th minute, while Conor did receive a straight red card for a needless strike with the hurl across the shins of the excellent Patrick Horgan (who was also red-carded for some unknown reason) off the ball two minutes from the end.
The midfielder is almost certain to be suspended for the final, while talismanic centre back Austin might face retrospective punishment for the same offence that saw Derek McGrath's men forced to line out without their sweeper Tadhg De Burca today.
Cork looked most likely winners when leading by 0-15 to 1-11 with twenty minutes left but the sending-off of Damien Cahalane turned the momentum in Waterford's favour and the winners - avenging their Munster semi-final defeat to the same opposition in June - outscored the Leesiders by 3-8 to 0-5 thereafter to ease across the winning line.
Walsh netted in the first half, while Man of the Match Jamie Barron twice struck goals in the second, either side of a magical solo effort from Austin Gleeson, who weaved a dizzying path through the Rebels reargaurd before poking to the net a minute after he had set up Barron with a delightful pass across the face of goal.
With 72,022 looking on, 'Brick' Walsh's fourth-minute major ensured the Suirsiders of the narrowest of leads at the end of a tense and low-scoring opening period, 1-7 to 0-9. Horgan - who finished the game with 0-12 - swept over seven of the Munster champions' first-half points, while Kevin Moran and Walsh were magnificent for Derek McGrath's men.
The gap would have been greater at the break but for an unbelievable Anthony Nash save to deny Pauric Mahony a second Waterford goal.
Horgan (free) and Mahony traded points inside the first three minutes and the unmarked Walsh collected a stunning pass from Shane Bennett to drill a low shot past Nash at the Davin End after Horgan had briefly restored the Rebels' lead.
Shane Kingston and Horgan pointed for Cork either side of a Moran reply and the Waterford captain registered his second point when Nash deflected his goal effort from a tight angle over the bar - 1-3 to 0-4 after nine minutes.
Alan Cadogan drilled over an inspirational Cork point at the Hill 16 end from the Cusack Stand side and Horgan equalised from a free (won superbly by Conor Lehane) in the 18th minute after a long passage of play without a score. But Moran lofted over his third to restore Waterford's lead and Horgan was on hand to bring the sides level for the third time.
Horgan and Mahony swapped frees, with Nash pulling off a sensational diving save to deny the Waterford No.11 in between. Mahony's free restored Na Deise's lead and Barron's sweet strike doubled the difference with four minutes left before the break.
Horgan's free halved the gap before the interval and Lehane's attempt at an equaliser with the last puck of the half came back off the right upright.
Horgan's long-range free drew Cork level in the second minute of the second half but Mahony replied from a free after great work from Moran and Barron. A soft Horgan free tied the scores up for the fifth time, 0-11 to 1-8.
Lehane's wonderful point was cancelled out by the on-fire Moran and Darragh Fives replied to an outstanding Horgan point before Darragh Fitzgibbon delightfully chipped a Cork sideline between the Davin End posts from beneath the Hogan Stand - but Mahony had them level for the eighth time at the end of a great Waterford move.
Seamus Harnedy re-established Cork's lead with 20 minutes left but the Rebels suffered a massive blow when full back Damien Cahalane was red-carded for a second-yellow card offence on 51 minutes (a high tackle on Conor Gleeson) and Na Deise moved ahead with quickfire points from Mahony (free) and Austin Gleeson.
Cadogan struck for the 14 men on 54 minutes and a Horgan brace edged them two ahead with 13 minutes left...
But Waterford goals from Barron and Austin Gleeson in the 58th and 59th minutes - with Conor Gleeson pointing in between - turned this game on its head as the winners suddenly led by five, 3-14 to 0-18. Mahony's free left six between them before Lehane pulled one back for the 14 men.
Substitutes Brian O'Halloran and Luke O'Farrell exchanged points and another replacement - Maurice Shanahan - added to the winning tally. Mahony clipped over his eighth and Conor Gleeson and Horgan were dismissed before Austin Gleeson pointed and Barron grabbed his second goal in the second of four added minutes.
So Waterford are into their first All-Ireland final in nine years - but at what cost?
Waterford - S O'Keeffe; S Fives, B Coughlan, N Connors; K Bennett, Philip Mahony, C Gleeson (0-1); J Barron (2-1), K Moran (0-4); M Walsh (1-0), Pauric Mahony (0-8, 6f), A Gleeson (1-2); Shane Bennett, J Dillon, D Fives (0-1). Subs: M Shanahan (0-1) for J Dillon, B O'Halloran (0-1) for Shane Bennett, T Ryan for M Walsh, C Dunford for Pauric Mahony, P Curran for J Barron.
Cork - A Nash; S McDonnell, D Cahalane, C Spillane; C Joyce, M Ellis, M Coleman; B Cooper, D Fitzgibbon (0-1sl); S Harnedy (0-1), C Lehane (0-2), S Kingston (0-1); A Cadogan (0-2), P Horgan (0-12, 7f), L Meade. Subs: M Cahalane for L Meade, D Kearney for B Cooper, L O'Farrell (0-1) for A Cadogan.
Referee - J Owens.