The station signed on in 1998 as KSOB with an oldies format as "Q Gold 95.7" owned by LA Media, and later changed to the KSQB call sign in 2001. KSQB was also owned by Feller Broadcasting, made up of a partnership of brothers Rob and Nick Feller. KSQB gradually tweaked to an adult contemporary format, and dropped the "Gold" from its moniker by April 1, 2004. Backyard Broadcasting acquired the station later in September 2006. With the growth of the adult hits format in 2005, Q95.7 gradually shifted to adult hits, and began reporting with the format to Arbitron by 2006.
The station was staffed by The Cartwright Brothers Morning Show (Weekdays 7 to 9 am) and Big Scott Allen (Weekdays Noon to 6pm.) Big Scott was also the program director of the station.
On November 1, 2012, Midwest Communications acquired KSQB-FM and its six sister stations from Backyard Broadcasting at a purchase price of $13.35 million.
On March 1, 2013, KSQB-FM changed their call letters to KQSF, changed their format to oldies, and rebranded as "Kool 95.7" (format moved from KXQL (now KELQ) 107.9 FM, which flipped to news/talk). Mark Cartwright hosts the morning show from 6am to 9am weekdays and is the brand manager of the station.