The 6-foot-11, 225-pound center from Santa Monica (Calif.) is Scout's 59th ranked 2016 prospect but he'll reclassify to 2015, graduate in December and enroll at Utah early.
Utah doesn't have a scholarship available, so Johnson's family will pay Jayce's way for the second semester while he's redshirting and then he'll go on scholarship for his redshirt freshman year.
"It was one of the hardest decisions of my life," Johnson told Scout. "At Utah, like every other place, I connected with all the coaches and players. I had a great experience. But what really stood out was Larry Krystkowiak.
"He's a big man and knows how I feel. He's been there and done that; he's been in the NBA. He knows what it takes and is going to teach me and give me the advice I need."
The relationship that Johnson built with Krystkowiak and his staff was a big part in his decision.
"I got to know the entire staff," Johnson said. "I talked to coach (Tommy) Connor, (Andy) Hill and (DeMarlo) Slocum. They all talked to me and I got to know all of them well. Larry called me whenever he got the chance and I really connected with him."
Utah sophomore center Jakob Poetl is a projected lottery pick in next year's draft and the way he's been used by Krystkowiak helped the Utes' recruiting pitch.
"I think I'll be similar to Jakob (Poetl)," said Johnson. "I'm a different person but I'll be used similarly. He'll utilize me the same way.
"He really uses the bigs in a way they should be utilized. The guards get the bigs the ball and it's great to be able to play for someone who cares so much about my position."
Krystkowiak has engineered a historic turnaround for Utah's program and that's helped Johnson's faith in his future head coach.
"The strides they've made over the last couple of years, they've come from nothing and he's gotten the teach so much better," said Johnson. "He knows what he's doing."