Banner will give the Trojans another elite prospect for a 2012 class that will be high on quality and low on numbers due to NCAA sanctions.
For Washington, it was another blow in a tough recruiting season. The Huskies have seen most of the best in-state prospects choose other programs, including offensive lineman Joshua Garnett (Puyallup, Wash./Puyallup), who picked Stanford, Keivarae Russell (Everett, Wash./Mariner), who picked Notre Dame, and Cedric Dozier (Lakewood, Wash./Lakes), who will pick between California and Washington State.
"The hardest part about this decision, and the thing that I was very nervous about, was letting down the hometown Husky fans," Banner told ESPN Recruiting's Greg Biggins. "They have been great with me and supported me like crazy over the last four years. I hope they can still be Zach Banner fans, because I need their support, and I've done my best not to make any enemies with anyone."
Meanwhile, USC and Stanford appear headed for a showdown on which program can sign the nation's best class of offensive linemen.
Banner is the fourth offensive line commitment for USC, joining Chad Wheeler (Santa Monica, Calif./Santa Monica), Max Tuerk (Rancho Santa Margarita, Calif./Santa Margarita) and Jordan Simmons (Encino, Calif./Crespi).
USC and Stanford are both finalists for highly rated offensive lineman Andrus Peat and Kyle Murphy.