The station, which signed on the air on September 1, 1967, was originally part of an AM-FM combo and had a successful easy listening format, which they broadcast from the Hilton Hawaiian Village on the beach at Waikiki during the 1970s and 1980s. It remained locally owned and operated until 1999, the same year the station shifted to adult contemporary and its AM sister station began its own programming. As of 2010, KUMU's direction has shifted to Rhythmic adult contemporary as "Hawaii's Old Skool", and added a nightly "Quiet Storm" show featuring Rico, which replaced the ailing syndicated "Delilah" program. In addition, its AM sister station once again became a simulcast for the FM station before changing its format and call sign in September, 2010 following the sale of the station (now KHKA). The station is programmed by radio industry vet Rick Thomas and is the #1 Arbitron rated station among adults 25-54 in Hawaii.