On May 13, 1958, the station signed on as KRSI. It was owned by Radio Suburbia and its studios were located at 4500 Excelsior Blvd. in St. Louis Park. On July 1, 1962, it started an FM sister station at 104.1 MHz, which, following many format changes, is now KZJK. At one point, both stations were owned by Red Owl Stores. In October 1972, the two stations moved to what is now the AM station's current studio and transmitter facility in Eden Prairie.