KRON-TV originally signed on the air on November 15, 1949, as a primary NBC affiliate. Although it was mostly owned-and-operated by the locally-based Chronicle Publishing Company, the network (who also owned AM radio station KNBC [now KNBR] at the time) fought for the construction permit but later lost to the Chronicle.
In April 1974, KRON introduced the original version of its current "4" logo, based on the design of the Golden Gate Bridge (the vertical component is a bridge tower, the horizontal component is a portion of the bridge deck, and the curve is a portion of a suspension cable). Station identifications used by the station during the 1970s and 1980s usually depicted the logo hidden in positive space within a full-scale design of the bridge; in the last two years of the logo's use, it became italicized. Though the next logo was introduced in 1987, this logo continued to be used on the station’s newscasts (then branded as NewsCenter 4) until 1988. It was briefly revived in late 2019-early 2020 to commemorate its 70th anniversary, only used on its promos for its documentaries.
This logo was introduced shortly before its NBC affiliation expired that same year.
On January 1, 2002, KRON-TV ended its affiliation with NBC after 52 years, the result of a 2000 dispute between the network and Young Broadcasting (which bought the station for $823 million in November 1999, outbidding NBC, which previously attempted to purchase the station several times while it was under Chronicle Publishing ownership) during negotiations to renew the affiliation contract set to expire on December 31, 2001, over reverse compensation and management demands inputted by NBC as stipulations for keeping the affiliation.
KRON-TV became an independent station by default, as ABC and CBS already ownedstations in the Bay Area, and Fox and The WB were under existing long-term contracts with KTVU and KBWB-TV; the NBC affiliation moved to San Jose-based then-The WB (and former ABC) affiliate KNTV.
KRON became a MyNetworkTV affiliate on September 5, 2006. At that time, the station instituted an alternate logo incorporating the MyNetworkTV and "Circle 4" logos for use in promotions for the service's programming.
1Nexstar operates these stations owned by Mission Broadcasting. 2Nexstar operates this station owned by Cunningham Broadcasting. 3Nexstar operates this station owned by White Knight Broadcasting through an SSA. 4Owned by Shield Media, LLC, Nexstar operates this station through an SSA, sale to Mission Broadcasting pending FCC approval. 5Nexstar operates this station owned by Vaughan Media. 6Predecessor company of LIN Media. 7Operated under local marketing agreement. 8Currently a repeater for WWLP. 9Joint venture with Discovery, Inc., in which Nexstar owns 31% while Discovery owns the remaining 69%.