It was a case of sweet revenge for the South Wales club, who lost out 6-5 to the Steelers in the final last year in the second period of overtime.
Like the previous year's final, the game started at a frantic pace but, after a few minutes, it was obvious there was not going to be the first period goal frenzy that occurred 12 months ago, with both team's playing a tight,cagey game - clearly aware of giving away too much too early.
Steelers' head coach Thompson made the one chance from the line-up that twice came from two goals down to beat Nottingham Panthers in Saturday's semi-final, forward Matt Marquardt the man to miss out with defenceman Miika Franssila coming in, a decision which saw Zack Fitzgerald move up to one of the forward lines.
There were half chances at both ends, but clear efforts on the respective goals were few and far between, last year's play-off final hero Levi Nelson first to force a pad out of Ben Bowns in the Cardiff goal while, at the other end, Ervins Mustukovs comfortably dealt with a couple of shots from Devils' Andrew Hotham.
The first penalty of theg ame was handed out to the Steelers when Swedish centre Andreas Valdix was sent to the box on a tripping call, but Cardiff failed to make it pay before Bowns was forced to react quickly to Rob Dowd's back-handed shot after the Steelers' forward had skilfully worked an opening for himself.
The second period carried on from where the first had left off, but a penalty call on O'Connor in the 25th minute proved costly. After the Steelers had broken down the ice through Mathieu Roy, the move broke down with Tim Wallace looking for a high-sticking call that never came. The Devils broke down the other end and, after a neat exchange of passes, Joey martin fed Matt Pope who fired past Mustukovs.
Dowd, Jonas Westerling and Fretter all had chances to elve, Dowd's from 10 yards out being the most clear-cut but denied by Bowns's right shoulder. As the Steelers pressed a soft second goal increased Cardiff's chances of doing the double when, from a face-off win on the right wing, Andrew Hotham was allowed too much time and space to fire the puck past into the top right-hand corner of Mustukovs's net.
As they knew they would have to, the Steelers came out with real purpose in the third, knowing that one slip would let the Devils in on a breakaway at the other end.
Mustukovs was forced to deny Reddick at full stretch with his left pad in the 45th minute before Dowd broke up the other end and made Bowns do the same with his right.
The goal the Steelers were searching for duly came at 46.55 when Eric Neiley picked up the puck in the neutral zone and drove down the centre before unleashing an unstoppable drive past Bowns into the Cardiff netminder's top left-hand corner.
In the minutes afterwards, Steelers piled on the pressure relentlessly and Valdix, Dowd and Nelson all went close to levelling for the Steelers.
Their hopes were lifted with just 85 seconds remaining when Devils' Sean Bentivoglio was sent to the box for roughing. With a minute left, they also pulled Mustukovs in preference for an extra attacker.
But after a few seconds the puck was worked out to Joey Haddad in the neutral zone who didn't need a second invitation to slot the puck into the empty net and seal the double for his team.