McLean travelled north to Pittodrie yesterday morning and, after undergoing a medical and completing the formalities, put pen to paper on a three-and-a-half year deal.
“My agent phoned me this morning to say a deal was on and it was a case of just getting in the car and driving up for the medical and the signing of the various papers,” said the 23-year-old, who has been allocated the No 7 shirt.
“Aberdeen is a club on the up, that’s for sure, and the ambition being shown by the gaffer with the players secured on long term deals, and the players coming in, was a massive incentive for me.
“I know a few of the lads from when I was a young kid, including Ryan Jack, Nicky Low and Clark Robertson, and this move feels exactly the right one for me at this time.
“I had some great times at St Mirren and I wish them all the best but I’m now an Aberdeen player which is fantastic.”
McLean, a former Scotland under-21 player, had 18 months left on his contract at St Mirren and last month was the subject of a £150,000 bid from English League 1 side Fleetwood Town.
He has been in excellent form in recent months, despite St Mirren struggling near the foot of the Premiership, and has contributed seven goals from midfield for the Paisley side this season, including two in his last three games.
Aberdeen lost Saturday’s League Cup semi-final against Dundee United and are already out of this season’s Scottish Cup, losing to Dundee back in November, but the Dons have so far kept in touch with Celtic in the race for the Premiership title and are currently three points behind the champions having played a game more.
And manager Derek McInnes last night expressed his great satisfaction at luring McLean north. “I’m delighted we’ve managed to secure Kenny on a long-term deal,” said McInnes. “He’s a good young player who is still improving all the time and I think in our team he will go and show how good a player he can be.
“We’ve signed a good player to come and play with the good players already here and it’s a real positive signing for us.
“I’d like to thank the board and the chairman for their support. I think this is the sort of signing that a club like Aberdeen should be making.”
St Mirren released a statement on their website confirming the deal. “When Kenny signed a two-year contract extension with the club last summer he put his trust in St Mirren and agreements were made,” it read. “St Mirren FC on receipt of the offer from Aberdeen FC have therefore honoured our side of the agreement as Kenny was keen to make this move.
“He kept his side of the agreement with his performances for the club this season. We would like to thank Kenny for all of his efforts and wish him well at Aberdeen.”
One of McLean’s new team-mates, goalkeeper Jamie Langfield, took to Twitter to welcome the midfielder to Pittodrie. “Welcome to the club @kennymclean66,” he wrote. “Another tremendous signing by the club, keeping the best Scottish talent in Scotland. #superb.”
McInnes also recruited a young defender a couple of hours before the midnight transfer deadline, with Borussia Dortmund’s Lukas Culjak agreeing a short-term deal until the end of the season, subject to international clearance.
The 18-year-old German, who started his career with Bayern Munich before moving to the Westfalenstadion in 2013, had been on trial at Pittodrie and is expected to form part of the development squad managed by Paul Sheerin.
As McLean and Culjak came in, striker Declan McManus left Aberdeen again yesterday, rejoining League 1 side Morton on loan until the end of the season.
McManus scored an impressive 12 goals in his recent loan spell at Morton and the Greenock club’s fans will be delighted to see the 20-year-old back in the squad for Saturday’s match against Stirling Albion.
Earlier in the transfer window, Aberdeen signed Inverness Caledonian Thistle captain Graeme Shinnie on a pre-contract agreement and, of course, they recruited central defender Donervon Daniels, who scored on his debut at Hampden in the weekend’s League Cup semi-final. Supporters eager for their team to mount a title challenge to Celtic will be delighted that no key players left the club, particularly midfielder Ryan Jack.