An injury-time goal won the cup in an incident packed final.
Mullingar were to suffer an early loss when captain Gerry Tarleton went off with a nose injury and Clara capitalised on this going in front after just 6 minutes when Shane Coyne hit a curling free-kick to the right of 'keeper Matthews.
The Westmeath side reacted well and drew level to get back into the game on 11 minutes, when a shot from Alan Graham was parried by Derek Handy allowing Enda Lambden a finish from close in.
Mullingar continued to press and went ahead on 26 minutes when a free kick from Noel Nugent was flicked into the net by Lambden from 8 yards out.
The pressure continued 29 minutes in, when the Clara right post was struck by Alan Graham followed by a fine tackle by Mark Mulvey to deny Mullingar's Mark Staunton a goal on 32 minutes.
The first half of injury-time saw both sides reduced to 10 men after an incident in the Mullingar penalty area.
The second half saw a second sending-off for Mullingar Town which altered the balance of play nine minutes into the half.
With just seven minutes left to play, Clara drew level whenJohn Devine, cutting in from the opposite flank, guided the ball past Matthews. Just when it looked like extra-time, Carroll's cross from the right was tipped over the crossbar by Matthews and the resulting corner saw Padraig Moran's strike, via deflection, land in the net.
(Gallen won 5-4 on penalties)
The shield final was a very close game with both defences very strong and chances for both sides very few.
Clonaslee started the brighter and gained a foothold in midfield with Aidan Phelan having the first chance from a header on nine minutes .
Jimmy Breen, the Clonaslee 'keeper, was then called into action - first, stopping a shot from Steve Hardie and then , catching a dipping cross from Kieran Gavin .
Clonaslee then had shots from Dermot Kelly and Brian Flannery before a tremendous headed goal line clearance at the other end by Declan Callaghan denied Gallen's Fergal McGuire the game's opening goal,
The second half started with Gallen putting on the pressure with shots from Steve Hardie and Martin Healy on 36 and 39 minutes.
Clonaslee responded with a header from Kelly and a pass from Sean Flynn to set up Joe Conroy who shot just wide .
Shane Molloy, with a free kick on 53 minutes and a header from Sean Flynn on 56, displayed Clonaslee's next efforts.
The last nine minutes of normal time saw Gallen on top and it took three tremendous saves from Jimmy Breen to keep his side level .
Into extra time and the deadlock was broken when Brian Flannery's long-range shot found the corner of the net five minutes into the first period.
Gallen went more direct but found Kevin O'Riordan in great form at the heart of the opposing defence .
In the second half of extra Clonaslee were coping with what was thrown at them until, with three minutes left, Joe Sheeran got onto a Fergal McGuire cross to equalise.
The spot kicks saw both sides scoring three out of the first five - both scored the first sudden death, Clonaslee missed and 'keeper Adrian Lynam stepped up to score and win the shield for Gallen.