The station has been a non-profit, listener-supported public radio station since May 2011.
KING-FM was once co-owned with KING (1090 AM, now KFNQ) and KING-TV (channel 5), but was donated to a non-profit partnership (consisting of the Seattle Opera, Seattle Symphony, and ArtsFund) by King Broadcasting upon that company’s sale to The Providence Journal Company in 1992. Even after the sale, the radio station was long co-located with the television operation. KING-FM moved to an office building several blocks away in 1999.
KING-FM began broadcasting in Seattle in 1948, originally at FM 94.9, owned by King Broadcasting co-owner Dorothy Bullitt. The year before, Bullitt had bought KEVR and changed it to KING. (Seattle is located in King County, for which its call letters were chosen.) Bullitt also owned KRSC-FM, which had gone on the air around 1947 at FM 98.1 under different ownership and been acquired by Bullitt in 1949. The classical-music station KING-FM moved from 94.9 frequency to 98.1 in 1958, replacing KRSC-FM. The transmitter at the 94.9 frequency was donated to Edison Vocational School, who used it to begin broadcasting KUOW-FM on that frequency.
During the late 1970s, KING-FM carried syndicated concert broadcasts by the Philadelphia Orchestra (usually under direction of Eugene Ormandy), the New York Philharmonic, and the Boston Symphony. Many of the syndicated concert programs featured well-known instrumentalists and conductors performing works which they never recorded commercially - e.g. Leonard Bernstein conducting the New York Philharmonic in a highly memorable 1976 reading of Bruckner's Sixth Symphony in A major.
In the mid-1970s, KING-FM's schedule also included specialized programs showcasing Quadraphonic LP recordings and historical recordings. In 1983, KING-FM was the first station in the Seattle area to utilize compact disc technology for its recordings.
In 1993, KING-FM relocated its transmitter from Seattle's Queen Anne Hill to Tiger Mountain near Issaquah. This higher-altitude transmitter location provided a vast improvement in the reception quality of KING-FM's signal throughout the Puget Sound area, and the Cascades.
KING-FM was also one of the first radio stations to broadcast its programming online, becoming one of the first internet radio stations.
Although KING-FM is owned by a non-profit entity, the station had continued to operate on a commercial basis. However, on March 23, 2010, KING-FM announced that it would transition to a public radio station in July 2011, citing reduced advertising revenue. Successful fundraising efforts led the station to announce on April 7, 2011, that the transition will instead take place on May 2, two months ahead of schedule.
In 2011, Classical KING FM 98.1 made the successful transition from a commercial to a non-commercial public radio station. Now as a listener-supported station, Classical KING FM 98.1 has added new programming and increased on-air music.