[16] Originating from WGN Radio's studios at the Tribune Tower's Centennial Building annex in the Magnificent Mile district, the inaugural broadcast included dedicatory speeches from McCormick,[c] Chicago Mayor Martin Kennelly, U.S.

[58][59][60] Tribune's later television purchases included those of WANX-TV (subsequently re-called WGNX, now WANF) in Atlanta (in 1983);[61] KTLA in Los Angeles (in 1985);[62] WPHL-TV in Philadelphia (in 1992);[63] WLVI-TV in Boston (owned from 1994 to 2006);[64] KHTV (now KIAH) in Houston (in 1995);[65] KTTY (now KSWB-TV) in San Diego (in 1996);[66] KCPQ and KTWB-TV (now KZJO) in Seattle (in 1998 and 1999, respectively);[67][68] and WBDC-TV (now WDCW) in Washington, D.C. (in 1999).

[79][80][81] WGN also served as a charter member of the Operation Prime Time syndication service, which was launched in 1976 as a consortium founded by Al Masini and a committee of executives with 18 independent stations (including WGN-TV, which was represented by then-station manager and WGN Continental Broadcasting Vice President Sheldon Cooper) represented by Masini's advertising sales firm TeleRep, offering a mix of miniseries as well as first-run syndicated programs that would be featured on the partner stations (including Solid Gold, Star Search and Lifestyles of the Rich and Famous, all of which aired on Channel 9 during the 1980s and early 1990s).

By the fall of 1978, the Channel 9 signal was transmitted to 574 cable systems—covering most of Western, Central and Southern Illinois as well as large swaths of Indiana, Wisconsin, Minnesota, Iowa, Missouri and Michigan—reaching an estimated 8.6 million subscribers.

[85][86] Within a week of attaining national status, WGN-TV added approximately 200 cable systems in various parts of the United States (reaching an estimated one million subscribers) to its total distribution.

Channel 32 began strengthening its syndication slate in the fall of 1979, when it acquired the local rights to off-network series such as M*A*S*H, Happy Days and All in the Family, which helped it edge ahead of WGN-TV in the ratings by the end of that year.

On September 18, 1981, Focus Broadcasting signed on Joliet-based WFBN (channel 66, now WGBO-DT), initially running a mix of local public-access programs during the daytime hours and the Spectrum subscription service at night.

[99][100] On November 22, 1987, during that evening's edition of The Nine O'Clock News, the WGN-TV signal was briefly overridden by video of an unidentified person wearing a Max Headroom mask and sunglasses in front of a sheet of corrugated metal imitating the moving electronic background effect used in the character's TV and movie appearances.

The extended video, as seen during the roughly 90-second-long hijack occurring later that night during a Doctor Who episode on PBS member station WTTW (channel 11), featured several references to WGN-TV (including the masked person mocking fill-in sports anchor and WGN Radio sports commentator Chuck Swirsky as a "frickin' nerd" and a "frickin' liberal", and referring to his pretend defecation as a "masterpiece for all the greatest world newspaper nerds", paraphrasing the WGN callsign's meaning).

Tribune committed six of the seven independent stations it owned at the time to serve as charter affiliates of The WB, though it initially exempted WGN-TV from the agreement, as station management had expressed concerns about how the network's plans to expand its prime time and daytime program offerings would affect WGN's sports broadcast rights and the impact that the potential of having to phase out its sports telecasts to fulfill network commitments would have on the superstation feed's appeal to cable and satellite providers elsewhere around the United States.

WGN-TV gradually evolved its programming slate during the late 2000s and 2010s, adopting a news-intensive format (expanding its newscast production to 70 hours per week by 2016), and shifting its weekday daytime lineup towards mainly first-run talk and game shows during the daytime hours; as fewer film packages were offered on the syndication market, its weekend schedule also began relying less on feature films and shifted to incorporate local lifestyle and tourism programs as well as additional first-run and off-network syndicated shows.

Starting with its addition to Comcast Xfinity's Chicago-area systems on December 16, the changeover allowed cable and IPTV subscribers within the market—as local satellite viewers had been able to do for about two decades—to receive WGN America for the first time.

[158][159][160][161][162] The WB and The CW each contractually limited the number of network program preemptions, other than those caused by long-form breaking news coverage, that could occur on an annual basis; in compliance with these restrictions, WGN-TV purchased airtime on CLTV (from 1993 to 2002), WCIU-TV (from 1999 to 2015) and WPWR-TV (from 2015 to 2016) to carry certain game telecasts that the station was contracted to produce (totaling roughly 30 per year).

For most of its run on the station (except in 1994, due to the Major League Baseball strike that year), WGN-TV would preempt portions of the telethon on Labor Day to carry Chicago Cubs or White Sox games held during the afternoon of the holiday.

The broadcast moved from syndication to ABC in September 2013 (by then reduced to a two-hour special), airing thereafter by association on WLS-TV until the final telecast of the retitled MDA Show of Strength in August 2014.

In August 1992, the Lottery awarded the telecast rights to its drawings and game show to CBS-owned WBBM—which beat out competing offers from WGN and WLS-TV, and saw the move as a way to help improve viewership for its third-place-ranked 10 p.m. newscast—effective December 28.

WBBM's bid was chosen for its offers to hold the drawings during its late newscast (which ultimately produced no beneficial ratings impact) and agreed to handle promotional responsibilities and production costs.

[212] Citing in part the station's statewide cable distribution (which, after the SyndEx rules were implemented, would occasionally subject the evening drawings to preemption associated with that of the delayed 9 p.m. newscast when sports clearance restrictions applied to the WGN national feed), the Lottery moved its telecasts back to WGN on January 1, 1994; with this move, citing declining revenues under the WBBM contract partly under the later drawing timeslot, the live evening results were shifted to 9:22 p.m.

Although WLS-TV has right of first refusal to MNF due to its corporate parent The Walt Disney Company's majority ownership of ESPN, WLS passed on carrying the game in order to air that night's live broadcast of ABC's Dancing with the Stars.

[255] However, on February 19, 2020, Chicago Fire FC announced a multi-year agreement with WGN-TV to broadcast their Major League Soccer (MLS) telecasts on the station, beginning with its March 7 match against the New England Revolution, returning regular sporting events to Channel 9 after a seven-month hiatus.

In May 1960, the late newscast (which, by that point, was anchored by Jim Conway, who also hosted a self-titled daytime talk show at the time) became the first local television news program in the U.S. to expand to a half-hour broadcast.

[266] In 1965, WGN appointed the first dual-anchor team ever employed in Chicago television news, as Gary Park (who came to the station from KCRA-TV in Sacramento) and Jim Ruddle (who previously worked at WTVT in Tampa) took the helm of the evening newscasts.

The Park-Ruddle combination was broken up in June 1967, when Ruddle left to join NBC-owned WMAQ-TV, to be followed two years later by Park taking a prime time anchor role at fellow independent KTVU (now a Fox owned-and-operated station) in San Francisco.

Skilling—who was rumored to have been the highest paid local television meteorologist in the United States—would become known for presenting his on-air forecasts with detailed but fairly easy-to-understand analysis and striking accuracy (most noted by his predictions of the Groundhog Day blizzard two weeks before it created paralyzing effects on the Chicago area in late January and early February 2011), and with routine usage of ensemble computer models to illustrate expected weather scenarios.

After briefly being relegated to weeknights following the shift to prime time, half-hour weekend editions of the 9 p.m. broadcast were added on October 4, 1980, anchored originally by Larry Roderick and Robert Jordan.

Weekend morning newscasts returned on October 2, 2010, with the debut of hour-long editions at 6 a.m. (shifted to a two-hour block at 7 a.m. on September 10, 2016, following Channel 9's disaffiliation from The CW, and expanded to a third hour on Saturdays until 10 a.m. on January 11, 2020).

[312] In October 1999, freelance reporter Jane Boal made headlines when she was hit from behind while trying to move away from a car attempting to drive away from an accident with another vehicle during a live midday report about a carbon monoxide leak that forced the evacuation of a school in the Rogers Park neighborhood; Boal (who was laid off by the station in May 2009) suffered cartilage and ligament injuries to both of her legs after being pinned between the car involved in the accident and a WGN live truck, but was able to resume work in early November.

(Incidentally, WGN-TV was one of six, originally eight, Chicago television stations that declined offers to move their analog transmitters to the Sears Tower antenna farm ahead of the building's 1973 completion.

[375][376] Though not a participant in the SAFER Act, WWME-CA carried simulcasts of WGN-TV's 9 p.m. newscast—except in the event of sports delays—and WMAQ-TV's morning and early evening newscasts until July 12 to provide an analog "lifeline" for viewers that were unprepared for or who had reception issues following the digital transition.

[377][378][379] In April 1985, the Canadian Radio-television and Telecommunications Commission (CRTC) approved eligibility for the signals of WGN-TV and fellow American superstations WTBS, WOR-TV and WPIX to be retransmitted as foreign services by multichannel television providers within Canada.