Channel 13 first signed on the air on September 17, 1948, as KLAC-TV (standing for Los Angeles, California), and adopted the moniker "Lucky 13".

Television personality Regis Philbin and actor/director Leonard Nimoy once worked behind the scenes at channel 13, and Oscar Levant had his own show on the station from 1958 to 1960.

On December 23, 1953, the now-defunct Copley Press (publishers of the San Diego Union-Tribune) purchased KLAC-TV and changed its call letters to the current KCOP, which reflected their ownership.

[7] In the early 1980s, KCOP became one of the many stations in the U.S. to broadcast Star Fleet (aka X-Bomber), a science-fiction marionette series which originally debuted in Japan in 1980.

Channel 13 aired select episodes of the Australian soap opera Neighbours from early June to late August 1991.

KCOP partnered with WWOR-TV and MCA TV Entertainment on a two night programming block, Hollywood Premiere Network starting in October 1990.

However, Viacom decided to continue operating KCAL as an independent, as Fox renewed affiliation agreements for its UPN-affiliated stations for four years, keeping the network's programming on KCOP.

With Fox's acquisition of KCOP, the station abandoned its longtime Hollywood studios at 915 North La Brea Avenue (once home to the classic Barry & Enright-produced game shows The Joker's Wild and Tic-Tac-Dough, and short-lived B&E entry Play the Percentages) with KCOP's news and technical operations being moved into KTTV's facilities at the Fox Television Center in West Los Angeles in 2003.

[14] The La Brea Avenue studio was put up for sale, with Fox electing to keep the facility, remodeling it to house the first two seasons of the reality series Hell's Kitchen.

[16] The studio was eventually torn down, and currently the site is now a Sprouts store, with a large apartment complex that opened November 2015.

In September 2006, the station began identifying itself as "MyNetworkTV, Channel 13"; the branding changed again in May 2007, simplified to "My13 Los Angeles".

On July 12, 2021, MyNetworkTV's programming was again moved to late-nights (midnight to 2 am), with off-network sitcoms filling the prime time hours.

[23] On July 3, 2023, KCOP replaced the simulcast of Catchy Comedy programming with airings of Law & Order: Special Victims Unit from 10 a.m. to noon, followed by the syndicated Dateline and TMZ Live.

Stars such as Freddie Blassie, John Tolos, Rocky Johnson, André the Giant and The Sheik headlined the shows, with longtime local announcer Dick Lane behind the microphone calling the action.

[26] From 2005 to 2007, KCOP carried St. Louis Rams preseason games produced by now-former corporate siblings Fox Sports Midwest and KTVI.

[37] On August 27, 2024, the Ducks announced that they would not renew their contract with Bally Sports, and would partner with both KCOP-TV and the Dallas Stars' free ad-supported streaming television (FAST) platform Victory+ to air all of its regional games, beginning in the 2024–25 NHL season.

During the 1980s, the station paired its local 10 p.m. program with the syndicated Independent Network News (which was produced by New York City's WPIX).

Channel 13's news programs generally were the lowest-rated evening newscasts of the seven VHF television stations in the Los Angeles market.

An ambitious attempt to relaunch KCOP's news operation came in January 1993, when the 10 p.m. newscast was renamed Real News and introduced a new format that featured anchors moving around the station's newsroom (similar to the format pioneered by CITY-TV in Toronto), in-depth reports, and newsmagazine elements.

After Fox purchased the station, KCOP's late-evening newscast took a more unconventional approach than its network-owned competition, KCBS-TV, KABC-TV and KNBC (channel 4).

In addition, it became the first station to emphasize entertainment and trend-setting feature stories as a major part of its format, an idea that attracted a large young demographic.

The network has also been added to the subchannels of Fox-owned MyNetworkTV stations in five other markets: WUTB in Baltimore, KUTP in Phoenix, WRBW in Orlando, KDFI in Dallas–Fort Worth and WFTC in Minneapolis–Saint Paul; the Baltimore affiliation had since moved to a subchannel of ABC affiliate WMAR-TV, soon after Fox sold-off MyNetworkTV outlet WUTB to Deerfield Media.

Buzzr, a new digital multicast network focusing on classic game shows, which is a joint venture of FremantleMedia (most notably, the owners of the Mark Goodson and Reg Grundy libraries among others) and KCOP's parent company, Fox Television Stations, debuted on channel 13.2 on June 1, 2015.

On September 18, 2015, Weigel Broadcasting and Fox Television Stations announced an affiliation agreement to carry diginet Heroes & Icons on subchannels of Fox-owned stations in New York City, Los Angeles, Dallas, San Francisco, Washington, D.C., Phoenix, Detroit, Tampa, Orlando and Charlotte beginning October 1, 2015.