The contract will be for five years and terms of the pact are unavailable.
Kent, who compiled a 235-174 mark during a 13-year stay at Oregon from 1997-2010, has 19 years of head coaching experience.
"Getting back into coaching for me has meant finding the right program that matches up with my passion, my vision, my beliefs and my commitment," Kent said. "And I feel Washington State University fits all that criteria for me,"
Kent will replace Ken Bone, who was fired on Mar. 18 after failing to guide the Cougars to the NCAA Tournament during his five-year stay in Pullman.
WSU went 10-21 this past season.