KYW's unusual history includes its call sign of only three letters, beginning with a K, rare for a station in the Eastern United States.

[3] In November 1920, the Westinghouse Electric & Manufacturing Company established its first broadcasting station, KDKA, located at its plant in East Pittsburgh, Pennsylvania, to promote the sales of its radio receivers.

The Westinghouse station was first licensed on November 15, 1921, as Chicago's first broadcasting outlet, with the randomly assigned call letters of KYW.

After the close of the opera season, KYW installed a studio in the Commonwealth Edison building, and began producing additional programming.

[7] In 1927, Westinghouse affiliated its four radio stations (KYW, KDKA in Pittsburgh, WBZ in Springfield and WBZA in Boston) with the National Broadcasting Company's (NBC) Blue Network, originating from WJZ in New York City, which had been transferred from Westinghouse to the Radio Corporation of America (RCA) in 1923.

Westinghouse fought a long legal battle, attempting to keep KYW operating as a clear channel station on 1020 in Chicago.

[24] On February 13, NBC changed KYW's call letters in Philadelphia to WRCV (for the RCA-Victor record label).

[26] The Westinghouse-NBC station swap, and its subsequent reversal nine years later, resulted in two alternate ways to recount KYW's history.

In the records of the FCC, the station in Philadelphia on 1060 kHz merely underwent two call letter and ownership changes, taking place in 1956 and 1965.

[30] Several months later in early 1960, NBC announced it would trade its Philadelphia stations to RKO General in exchange for that company's Boston outlets, WNAC-AM-FM-TV.

The Commission renewed NBC's licenses for WRCV radio and television, on the condition that the 1956 station swap with Westinghouse be reversed.

[33] Following nearly a year of appeals by NBC, Westinghouse regained control of WRCV-AM-TV on June 19, 1965, and subsequently restored the KYW call letters to the radio station.

[34] On September 21, 1965, shortly after Westinghouse regained control of 1060 AM, the newly revived KYW dropped its NBC radio affiliation.

KYW-TV took advantage of the radio station's popularity by incorporating a version of KYW's musical sounder into its news themes from 1991 to 2003.

[38] That station, under its original WCAU call letters, had attempted during the late 1970s to compete with KYW with all-news programming.

[39] The station previously used the HD Radio digital system created by iBiquity beginning in 2007 after an initial testing period.

[40] In March 2007, the studios moved one half-block to 400 Market Street in Center City Philadelphia, which allowed for the construction of the National Museum of American Jewish History.

In March 2014, KYW radio and television relocated to the sixth floor of 1555 Hamilton Street in Philadelphia, in what was initially referred to on-air as the "CBS Broadcast Center".

[41][42][43][44] KYW radio ended its longtime partnership with KYW-TV on February 10, 2020, and began broadcasting traffic, news, and weather information from NBC-owned WCAU (channel 10).

[45] KYW broke from its all-news format on November 3, 2022, to simulcast Game 5 of the 2022 World Series, which involved the Philadelphia Phillies, with WPHT.