WJLB, along with sister WMXD, broadcast for 20 years in Detroit's Penobscot Building in the heart of the financial district. iHeartMedia, Inc. moved both stations to a building in Farmington Hills in November 2009.
WJLB's transmitter is located in Highland Park near the intersection of Hamilton Avenue and Midland Street, and transmits its signal from an antenna 489 feet in height with an Effective radiated power of 50,000 watts.
The station traces its origins to a testing station which began operations on May 7, 1941, with 1,000 watts of power at 44.9 megahertz frequency. On May 24, it officially began broadcasting as W49D, Michigan's second FM radio station. It was owned by John Lord Booth, who was born in Detroit on June 13, 1907, and died in Grosse Pointe Farms on November 11, 1994, at the age of 87.
97.9 signs on as WMZK
On September 12, 1945, W49D was assigned a full-powered frequency at 96.5 MHz and renamed WLOU. In June 1948, the station moved up to the 97.9 frequency as WMZK, which was a play on the word music, with a format of automated beautiful music. In later years, WMZK alternated between beautiful music and foreign-language programming for various ethnic groups.
In 1980, the WJLB callsign migrated to the FM dial at 97.9, alongside with an Urban Contemporary format from the 1400 kHz AM frequency. WJLB-AM, which went on the air as WMBC in 1926 and adopted the WJLB callsign in 1939, had been providing programming geared toward Detroit's black community for nearly four decades.
Throughout the 1980s, the stereo FM station was transformed as a CHR/Urban Contemporary (also called "CHUrban", which would be the forerunner to the current Rhythmic CHR format) known as WJLB FM98, Detroit's Strongest Songs!, which would gravitate back to a full-blown urban format. WJLB-AM continued to program to the African-American community in Detroit for nearly a quarter-century afterward as WQBH, and is now WDTK, owned by Salem Communications with a conservative news/talk format. Within a few years, WJLB-FM performed well in the Detroit Arbitron ratings, despite picking up competition from several competitors, including WHYT, which was mostly dance and Top 40, but in 1992, would flip to "96.3 Jamz" and aired a rhythmic contemporary format, and then in 1996 at the 105.9 frequency, the former jazz-formatted WJZZ, which became WCHB-FM "The Beat", and later WDTJ "105.9 Jamz" (now urban AC-formatted WDMK "105.9 Kiss-FM"). FM98 was famous for its specialty Friday mix shows with "Electrifying Mojo" and the "Sunday Night Segue," hosted by John "Johnny Smooth" Edwards, featuring classic "Quiet Storm" tracks, as well for the highly successful morning shows that made WJLB the strongest station in Detroit from John Mason and his legendary "Mason And Company" morning show all the way to MC Serch of 3rd Bass and his morning show.
In April 1994, Booth American Company merged with Broadcast Alchemy to become Secret Communications. In August, Chancellor Media acquired the station from Secret Communications. In 1997, Chancellor Media and Evergreen, which already owned WKQI "Q95.5" and WQRS, later merged to form AMFM, Inc. In November 1999, AMFM, Inc. was purchased by Clear Channel Communications. WJLB and sister station WMXD have been under the Clear Channel banner ever since. Over the last several years, WJLB has shifted to a more younger emphasizing playlist with more Hip Hop and less Old school and House music which the station was built on in the 1990s through 2005.
As of October 2017, the station rebranded as "97.9 WJLB".