While the fee is undisclosed, the suggestion is that it is in the region of £11m. This would mean that the former Leeds player becomes the second most valuable Scottish player, at just £2m below what Everton paid to sign James McCarthy from Wigan last summer.
That is more than the £10m that Liverpool paid for Brazilian international Philippe Coutinho and just £1.2m less than the amount Sir Alex Ferguson paid to sign Cristiano Ronaldo back in 2003.
McCormack has signed a four-year deal at Leeds, with the possibility of a one-year extension after that.
The transfer came after reports that Fulham had a £5m bid for the striker knocked back last week and means that, despite dropping to the Championship, the west London club will have a front pairing worth £23m. This is thanks to the £12m they spent in January on Greek forward Kostas Mitroglu, who has played only twice for the club.
The most expensive transfer involving a British striker was Andy Carroll's blockbuster move from Newcastle to Liverpool on January 2011 transfer deadline day, the same day that saw Fernando Torres sign for Chelsea for a record £50m. Wayne Rooney commanded £26.5m in his move from Everton, while Aston Villa paid £18m to sign Darren Bent.
England internationals Peter Crouch and Emile Heskey were also judged to be worth £11m.
In the top 10 transfer fees paid involving a British forward, all except McCormack's move have been made by Premier League clubs.
But given that Felix Magath's side will receive parachute payments in the aftermath of their relegation from English football's top tier, shelling out on an established Championship striker, proven at this level, might make sense in the long run.
McCormack was one of the Championship's star players last season, involved in more goals than any other player in the division. The 27 year-old Scot had a hand in 37 goals for Leeds, netting 28 times for his club.
While the fee may have already raised eyebrows and provoked reaction from fans, if McCormack can help Fulham back into the Premier League next season, with the riches on hand for promoted clubs believed to be in excess of £100m, then £11m may actually prove a smart investment.