The origin of this station goes back to legendary radio owner, Gene Chenault. He owned the "Boss Radio" KYNO (AM 1300). The FCC granted a new license to the frequency 95.5. Call letters were KPHD. The first music to be played was the automated "Hit Parade '70" in early 1970. Boss Radio was on the AM side and the Drake-Chenault provided programming kicked off the FM. 95.5 KPHD would move up the dial to 95.7 eventually. KJFX was originally an automated country music format adopting the call letters of KYNO-FM. The format was later changed to a rock format adopting the call letters of KPHD, branded as "Rock 96 FM". In the 1980s, the format was changed to Top 40 branded as "96 FM" to compete with KBOS and KMGX. In the late 1980s, the branding was changed to "Hot 96".
In February 1990, the format was changed to a classic rock music format with a change to its present call letters, KJFX.
The Fox remains a high ranking music station with men in Central California despite the emergence of several similarly formatted stations in recent years. Current staff/programing consists of the Bob and Tom Show, Carter, and Koyote Kris.