The Welshman prodded home a backheel from Olivier Giroud in the second period of extra-time to condemn Steve Bruce's side to a 3-2 loss at Wembley.
|VIEW FROM WEMBLEY
|By Greg Stobart
Arsenal are the FA Cup winners and that horrible statistic of no trophy since 2005 has finally been put to rest after this Wembley thriller.
The expectation of the Gunners supporters was evident as they piled up Olympic Way and the atmosphere at kick-off was as loud as this stadium has witnessed since being rebuilt.
This Arsenal side, and in particular Arsene Wenger, have answered some huge questions today, not least about the strength of their character.
They had to do it the hard way after falling two behind to early goals from James Chester and Curtis Davies - but Arsenal controlled most of the game and deserved to win.
A brilliant Santi Cazorla free-kick and a Laurent Koscielny close-range strike made sure the game went to extra-time and after waiting for nine years, what did another half-an-hour matter.
Hull worked relentlessly but Arsenal made their quality count in extra-time, particularly Aaron Ramsey. The Welshman continually bombed forward and finally found the winner with a sharp low finish to send 30,000 or so Gunners fans wild.
Arsene Wenger's side were stunned by Hull, who scored twice inside the opening eight minutes, first through a reaction flick from James Chester before Curtis Davies cooly slotted home from a tight angle.
Santi Cazorla reduced the deficit soon after with a long-range free kick with Laurent Koscielny equalising 19 minutes from time before Ramsey claimed the cup in the closing moments.
Fabianski kept his regular cup berth between the posts, despite doubts over his future with the Emirates Stadium club, while Chester recovered from a hamstring injury in time to step into a new-look Hull back line.
Chester's inclusion proved to be an inspired decision from manager Steve Bruce as the defender stunned Arsenal fans into silence by breaking the deadlock in the fourth minute.
A low 20-yard strike by Huddlestone fizzed towards Chester's feet, and his touch in the centre of the penalty area was enough to send the ball beyond an outstretched Fabianski, finding its way in off the left-hand upright.
In the absence of cup-tied forward pairing Shane Long and Nikica Jelavic, it was Hull's defenders running riot in the opening stages.
Fabianski leapt to his left to keep out an Alex Bruce header, before fellow centre-back Davies rifled home from a tight angle, though question marks were raised over the positioning of the free-kick that led to the goal.
Another Alex Bruce header from a corner threatened to make it a defensive hat-trick for the underdogs, but Kieran Gibbs came to Arsenal's rescue on the goalline.
There was no let-up in the action, and Arsenal were right back in the tie in the 18th minute.
Cazorla curled a 25-yard free-kick into the top right-hand corner of the net - Hull keeper Allan McGregor wrong-footed by the Spaniard's stunning strike.
There was a nervous edge to the match after the break, and Giroud felt he should have been awarded a penalty in the 58th minute after having his shoulder held by Huddlestone.
Further penalty shouts followed as Jake Livermore appeared to handle from a Yaya Sanogo header and Cazorla was felled by Davies, but referee Lee Probert was unmoved by the appeals.
After looking the more likely to find the net in the second period, Arsenal finally pulled level, Koscielny turning the ball in from close range in the aftermath of a contentious corner.
An unmarked Gibbs should have sealed the trophy for Arsenal in the 79th minute, but the full-back blazed over from close range when it appeared easier to score, and McGregor got down well to deny Giroud from 18 yards three minutes later.
Substitute Sanogo sent a strike whistling wide of the left-hand post before the end of 90 minutes, and Giroud rattled the crossbar in the opening stages of the additional period.
The match looked to be heading for penalties as the tempo of the game dropped, but Ramsey popped up to end nine years of hurt for Arsenal and Wenger, though Fabianski's late charge off the line had many a heart in mouth as Sone Aluko's effort drifted agonisingly across the face of goal.