The 53-year-old Sumlin was let go at Texas A&M last season.
Prior to his time with Texas A&M, Sumlin spent three years as the head coach of Houston, taking the reigns as head coach in 2008 and leading the Cougars to a victory in the Armed Forces Bowl in his first season.
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Arizona has one of the most exciting quarterbacks in the country in Khalil Tate, who was the PAC-12's newcomer of the year.
The Arizona Wildcats on fired football coach Rich Rodriguez earlier this month after six seasons in the wake of a sexual harassment allegation and a recent notice of a hostile-workplace lawsuit to be filed against Rodriguez.
If he can replicate the success he had at the end of his Houston tenure and beginning of his time at Texas A&M, Sumlin's new team figures to compete for conference championships in the coming seasons. Sports Illustrated's Bruce Feldman reported Sumlin will retain UA defensive coordinator and interim head coach Marcel Yates, who coached under Sumlin at Texas A&M.
However, Texas A&M didn't finish above.500 in the SEC in any of Sumlin's final five seasons with Texas A&M as his stock dropped.