Knowlton had served as the Bears' athletic director since the spring of 2018.
The Bears beat out UNLV for the three-star defensive lineman from Corona-Centennial on Sunday.
The Bears edged out BYU for a commitment from the Kailua High School star offensive tackle recruit.
The visit to Berkeley last weekend moved the 6-foot-4 defensive lineman from Texas closer to a decision.
The 6-foot-5 recruit has been on the rise this spring with offers from Virginia, South Florida, UCF, UTSA and others.