Gates, who will be officially introduced at a news conference on Tuesday, has been an assistant coach under Leonard Hamilton at Florida State for the past eight seasons. He also has spent time at Marquette, California, Northern Illinois and Nevada.
He replaces Dennis Felton, who was fired on July 12 after going 22-44 in his two seasons.
"I have dreamed for a long time about serving as a head coach and am humbled and honored to be trusted with this opportunity at Cleveland State University," Gates said. "My family and I are filled with great joy and excitement. ... I am looking forward to rolling up my sleeves and working with our student-athletes to win championships in the classroom, on the court and in the community."
Eight Cleveland State players have entered the transfer portal since June 12, including four since Felton was fired. That group includes the team's top five scorers, led by all-conference guard Tyree Appleby (17.2 PPG, 5.6 APG), who ended up at Florida. Guard Rasheem Dunn, who sat out last season after averaging 15.4 points at St. Francis Brooklyn, also decided to leave.
There are just three returning players on the roster.
"It was important to identify a leader of young men who was totally invested in delivering character, accountability, professionalism and an unparalleled passion for developing student-athletes on and off the court," athletic director Scott Garrett said. "After carefully evaluating an impressive pool of interested candidates, Dennis Gates rose to the top and won this position with his thoughtful plan for transforming the lives of CSU men's basketball student-athletes, regaining our competitive position in the Horizon League and building a program that is representative of all of the incredible momentum occurring on the campus of Cleveland State University."