The 6-foot-3, 200-pound Johnson passed for 3,210 yards and 34 touchdowns with only seven interceptions as a sophomore at College of The Desert. A dangerous dual-threat quarterback, he also rushed for 429 yards and eight scores.
He picked UK over scholarship offers from Hawaii, Eastern Michigan, Florida A&M and Arkansas State.
Johnson, who started his college career at Grambling State University, will have two years of eligibility remaining. The Rancho Cucamonga, Calif., native will enroll for this semester and be ready to participate in spring practice with the Cats.
Quarterback became a huge priority for UK in this recruiting class when Patrick Towles and Reese Phillips both announced they were transferring in December. That left the Cats with only one scholarship quarterback on campus, starter Drew Barker. Kentucky also expects to have early enrollee Gunnar Hoak, a high school prospect from Ohio, for spring practice.
Inconsistent quarterback play was a big part of UK's disappointing 5-7 season in 2015. The Wildcats threw only 10 touchdown passes while tossing 16 interceptions. After Towles was benched, Barked started the final two games of the season, completing 35 of 70 passes for 364 yards and one touchdown with two interceptions.