The University's first mascot was Sunny Boy, a 3-foot-tall (0.91 m), gold-painted statuette representing an illustrated character frequently appearing in Columns, which - at the time - was a student-published campus humor magazine (presently Columns is the title of the University of Washington Alumni Magazine). The mascot was introduced in 1920 and retired three years later when the University adopted the nickname "Huskies." 
Beginning in 1922, the University used live sled dogs as its mascot, first a non-hereditary line of Siberian Huskies and, beginning in 1961, a hereditary line of Alaskan Malamutes.  Due to the size of the animals, difficulties of travel logistics and handler schedules, the mascots would generally only appear at home football games.
In 1995, officials in the University's athletic department commissioned a costume and held tryouts for the new live mascot. Three student performers were chosen (Lee Harris, Evelyn Ho and Chris MacDonald) and rotated duties to appear as a secondary mascot for use at events at which the live mascot was unable to attend. A contest and public vote two years later named the new mascot "Harry the Husky."  Coincidentally, the mascot had already been referred to by that name during a scene in The Sixth Man, a film starring Marlon Wayans about the University of Washington basketball team, that had been released prior to the vote.
In 2010, the University unveiled a new Harry the Husky costume and retired the old one. The new husky made his debut on October 9, 2010.