Minor co-channel interference is common on CJBK at night from WHIO in Dayton, Ohio, which also broadcasts on 1290 kHz.
CJBK went on the air January 25, 1967, as CJOE. "JOE" in the call letters stood for H. J. McManus, the founder of the station (under the banner of Middlesex Broadcasters, Ltd.). The station originally featured a Beautiful Music format. Eventually CJOE began to supplement the easy listening music with soft rock and then Top 40 music during the evening hours, but the station remained unprofitable.
In 1972, McManus sold the station to Rick Richardson (two-thirds Baron Communications, Ltd. and one-third Bruce Communications, Ltd.). On September 6, 1972, Richardson took control of CJOE and changed the call letters to CJBK and the format to full-time Top 40 hit music. Richardson wanted a "CJ" call sign to distinguish the new AM 1290 from its competitors CFPL and CKSL, but it has also been suggested that the CJBK calls were a personal tribute to former Detroit Top 40 station WJBK-AM, which had been a favourite station of Richardson's while he lived and worked in Windsor. CJBK's main catchphrase in the 1970s was "Have a Good Day!" In 1980, CJBK added an FM sister with country-formatted CJBX-FM 92.7.
In 1987, CJBK and CJBX were acquired by Middlesex-Lambton Broadcasters Ltd., and CJBK shifted from its CHR format to Adult Contemporary in August of that year. The station began broadcasting in AM Stereo in 1989. In early 1992, the station changed format from AC to Oldies.
London Communications, Inc. acquired CJBK and CJBX in September 1993 and shifted CJBK from oldies to the current news/talk format on August 12, 1996. The stations were sold again in 1999, to Telemedia, which already owned AC CIQM-FM and would purchase CKSL-AM the following year. Standard Radio acquired Telemedia's London stations in 2002.
In October 2007, Astral Media acquired Standard Broadcasting's terrestrial radio and television assets, including CJBK.
Morning host Steve Garrison has been a fixture on CJBK since the late 1970s. After a stint as station promotion manager, Garrison became a mid-day DJ in January 1984, and began co-hosting a morning show in 1990 with future CBC News anchor Heather Hiscox. After moving back to middays for a few years, he began hosting his current morning show when the news/talk format was adopted in 1996.
(The former CJOE call letters in London, were also used in Ottawa, Ontario, later Witchekan, Saskatchewan. It's uncertain if the CJOE callsign where also used by any other radio station in other locations in Canada.)