"They've been there from the beginning, since eighth grade. They were the first school to recruit me," Williams said of Arizona. "The addition with [assistant] coach [Lorenzo] Romar only helped me out. They are starting to do a lot more ball screens, which fits my game. Also, my relationship with the coaching staff is great. That's very important."
Williams made his announcement public in a tweet Tuesday evening that he addressed to the University of Arizona.
Williams, a 6-foot-1 point guard from Crespi Carmelite High School (California), is ranked No. 16 in the ESPN 60 for 2018. He slots in as the No. 3 point guard in the country. Williams missed his junior season and the spring AAU circuit due to a knee injury, but his recruitment didn't slow down.
The Wildcats zeroed in on Williams as their primary point guard target in 2018 early in the process.
"They need me to be the point guard," Williams said. "They haven't had that guard in a while. They need me to just do what I do now: create for myself as well as for my teammates."
Arizona coach Sean Miller has landed a top-seven recruiting class in seven straight seasons, and he already has two five-star recruits in the fold for 2018. Williams joins five-star power forward Shareef O'Neal (No. 19), the son of Shaquille O'Neal. Former five-star prospect Emmanuel Akot committed for 2018 but recently reclassified into 2017 and will enroll at Arizona for the upcoming season.
Arizona has its eyes on a big 2018 class, with No. 1 prospect Marvin Bagley III atop the list.
"Shareef and I are both assistant coaches," Williams said. "We are definitely going to recruit some guys."