The team came from a goal down to beat Aberdeen 2-1 in their semi-final earlier today to reach the final for the first time in the club's history.
The manager told Sky Sports News: "It means everything for the club, the supporters and the players. They've put a lot into this season and now we've got a cup final. I thought they were magnificent and I don't think anyone can begrudge us the result.
"We stayed in the game and were always a threat, so I'm really pleased. This club doesn't get the publicity I feel it deserves. It's a really great day all round for everybody."
St Johnstone will face Dundee United in the final next month.