McCormack, 27, moved in an incredible £11m deal between two clubs in the English Championship, joining Fulham on a four-year deal with an option of a fifth.
Steven Fletcher, who cost Sunderland £12m, is the only Scottish striker who has ever moved for more. McCormack could make his Fulham debut in a friendly at Motherwell on Saturday.
But no sooner had the transfer been announced than Leeds owner Massimo Cellino heavily criticised McCormack and claimed the player had forced the club into a sale. "I was disrespected and he was aggressive with me," said Cellino.
"I like to be in control of situations but it felt like he wasn't my player. He didn't turn up for the tour to Italy and all the time he wanted to go from here. It wasn't in my mind to sell McCormack, it wasn't my plan, but I had no choice. He's a bloody good player and I'm not going to pretend that he isn't but he didn't respect me and it wasn't possible to keep him."
McCormack began his career with Rangers but struggled to break through and after a loan to Doncaster Rovers he joined Motherwell in 2006. After two fine seasons at Fir Park he joined Cardiff City before moving again to Leeds in 2010. Last season he scored 29 times, making him the Championship's top goalscorer. He was wanted by Norwich City as well as Fulham, who finally landed him after two earlier, unsuccessful attempts.
The fee was so high partly because Fulham benefited from a parachute payment having been relegated from the Barclays Premier League, and partly because Leeds had re-signed him on a new deal last season and he was under contract with them until 2017.