On August 20, 1963, KLWN-FM first signed on. Its original purpose was a full-time signal to broadcast weather, sports, and other information, including things like school closings. The FM station was originally run by a tape, at that time the station's most popular programming was University of Kansas or Lawrence High football games.
The station started with technical facilities of 17 kW on 105.9 MHz. From 1963 to 1974, both stations shared the same studio. KLWN-FM essentially simulcast the AM during daylight hours until 1972. In 1972, the staff began a separate rock programming that was broadcast in the overnight hours, first after the AM sign-off, and then it was pre-taped and replayed the next day at 3 PM, later noon. On April 1, 1974, an addition to the station allowed the AM to move into a new studio (complete with an interview room) and the FM to have the old one. For several years, "The Music Station 106" was the FM on-air name. Then on July 31, 1979, KLWN-FM received the new calls of KLZR and was authorized to increase power to 100 kW. The new 550-foot tower was completed and the new transmitter was put in use in December.
During the 1990s, KLZR carried a modern rock format, which was popular on the KU campus and in the college town atmosphere of Lawrence; even garnering a mention in Rolling Stone magazine as one of the top ten "Stations that Didn't Suck" in 1998. The station was independently owned by the Booth family until they sold out on Sept 1, 1998. The Zimmer Radio Group assumed ownership until ZRG member Jerry Zimmer separated the station from the group in 2005, returning KLZR to a local ownership status under the incorporated name "Great Plains Media". After the Booths' sold out in 1998, KLZR morphed into a Top 40 station. In 2003, the station shifted formats again, this time to a Hot Adult Contemporary format.
On January 20, 2012, KLZR began stunting with all-Lady Gaga music. Later that day, at 3 PM, the station re-branded as "105.9 Kiss FM" and returned to a Top 40 format. On February 7, 2012, KLZR changed call letters to KKSW to match the new branding.