In a episode filled with celebrity performances and "favorite" dances of the season, Ferguson, who suffered an injury in Tuesday night's performance, beat highly-trained contemporary dancer Jakob Karr for the title.
In the six-way finale, dancers were eliminated in this order: Ryan Di Lello, Ashleigh DiLello, Ellenore Scott, Kathryn McCormick and Jakob Karr.
Special guests who performed were Leona Lewis, Mary J. Blige, Adam Lambert and Jennifer Lopez.
Ryan and Ashleigh were the first married couple to compete on "So You Think You Can Dance" and Ryan, when he was eliminated, told host Cat Deeley that the best part of his journey was "sharing it with my sweetheart."
Earlier in the evening, judge and producer Nigel Lythgoe described Jakob as "a polished diamond" and Russell as a "diamond in the rough," and said both were superb dancers.
When his name was announced as the winner, Russell hopped up, despite his injury, and tore off his shirt. He said he had been dreaming of this moment "since I was born."
During the two-hour show, contestants performed dances that the judges and choreographers had chosen as their favorites of the season.