The Reds were far too good for their opponents who lost their way when they had Paul Heatley send off with 30 minutes left to play.
At that stage Cliftonville were in the driving seat leading 2-0 and they went on to add some gloss to the finish and set up the first leg of a possible treble for Tommy Breslin's side.
Both teams are used to playing on a plastic pitch but had to endure a heavy, muddy pitch with constant rain, but they did serve up a superb cup final.
"It's a great feeling to finally win a big trophy like this," said a delighted George McMullan. "This is only the start for this team. This is going to be a special year for Cliftonville Football Club."
There was a frantic start to the game with both teams having chances to score in the opening minutes.
First Jordan Owens connected with a cross from Gareth McKeown which went straight into the arms of keeper Conor Devlin and then Liam Boyce slipped the ball to Barry Johnston who dragged his shot wide of the goal - all within the space of two minutes.
Owens got in behind the Reds defence in the next attack but Devlin raced out to dive low to push his shot away for a corner.
The action continued with Chris Morrow playing a lovely back heel ball to Paul Heatley but he could not hit the target. It was Timmy Adamson for the Crues as he let fly from 20 yards out and Devlin had to divert the ball over the upright for a corner.
The bright start for the Crues continued with a Heatley corner met by dangerman Colin Coates and it looked as if Devlin was beaten but he managed to stick out his boot to clear the ball off the line.
On 13 minutes Boyce squared the ball to Stephen Garrett and his firm drive brought a fine save out of French goalkeeper Lacroix who was called upon again two minutes later to deny Joe Gormley.
The opening goal arrived on 22 minutes and it had a touch of good fortune for the Reds as Garrett did well to get past two markers, passed to Boyce who rolled the ball into the path of Diarmuid O'Carroll whose low drive clipped off the legs of McClean on the way into the net.
The Crues had hardly time to recover from that blow to find themselves two down three minutes later.
Barry Johnston fed Boyce, he pulled the ball into the middle and Gormley just managed to get a toe on the ball ahead of defender McKeown.
Stephen Baxter's side tried to get back into the game with efforts from Heatley and Owens but it was the Reds who went closest to finding the net when Boyce chested the ball down to Gormley who teed it up for Boyce but his angled drive flew across the face of the goal.
Just before the end of the half a quick free kick by Johnston saw Boyce pick out Gormley but the keeper did well to block his goal-bound shot.
The second half was barely seconds old when Gormley did well to win the ball from Magowan and lob a cross into the box and Boyce just failed to connect in front of a gaping goal.
Any hopes the Crues had in mounting a comeback all but ended on 60 minutes. Heatley lost possession and his discipline when he dived in from behind to floor George McMullan and referee Arnold Hunter had no option but produce a red card.
David Rainey came off the bench and almost pulled a goal back with a snapshot that deflected wide while at the other end Gormley was denied by the legs of the keeper.
The base of the post prevented the Reds from a third goal on 69 minutes after a great run from Ronan Scannell saw his shot from a tight angle come back off the woodwork.
With so much possession it was no surprise Cliftonville did find the net again, sub Cosgrove slipping a lovely ball into the path of Gormley and he made no mistake to notch up his 22nd goal of the season.
Two minutes later it was all over when Boyce played the ball into the box, Coates could not clear the ball and Catney ran on to plant a shot past the keeper and in off the post.
Gormley had a great chance to claim his hat-trick on 90 minutes but missed from a yard out after a great run and cross from Seydak.
In the end however, it did not matter, the final whistle brought loud cheers from the Cliftonville fans who last saw their team lift this trophy ten years ago.
Cliftonville: Devlin, McGovern, Scannell, Johnston, McMullan, Garrett, O'Carroll, Smyth, Catney, Gormley, Boyce. Subs: Holland, Donnelly, Seydak, Cosgrove, Knowles.
Crusaders: Lacroix, McKeown, Magowan, Coates, Morrow, Adamson, Robinson, Caddell, McClean, Owens, Heatley. Subs: McBride, Leeman, Rainey, Snoddy, Hyland.