WPFB-FM first signed on in 1959. WPFB-FM was the first FM station in Ohio and the 13th in the United States to broadcast in stereo. Like its AM sister,WPFB-FM had several format changes over the years. It was a soul gospel music format in the late 1970s switching to soft adult contemporary WPBF "Mellow 106" in the early 1980s, then switching again to new rock in 1984, southern gospel in 1986 and bluegrass music in 1988 when the calls were switched back to WPFB-FM where it has maintained a country music format since.
Beginning on February 1, 2011; WPFB-FM, along with its sister station WPAY-FM 104.1 in Portsmouth, Ohio, began simulcasting the signal of Northern Kentucky University-owned WNKU. At that time, WPFB and WPAY switched from a country format to an adult album alternative (AAA) format.  The sale was approved by the FCC on June 20, 2011 and the station officially changed their call letters to WNKN on that date.