The station reaches much of the population of Ontario through a network of 12 transmitters across primarily the southern and central portions of the province (as a result, it is the de facto Global outlet for the capital city of Ottawa through repeater CIII-DT-6).

Ken Soble, the founder of CHCH-TV in Hamilton, envisioned a national "superstation" of 96 satellite-fed transmitters with CHCH as its flagship.

The Canadian Radio-television and Telecommunications Commission (CRTC) eventually decided to go ahead with the publicly owned Anik satellite system instead of relying on private communications companies to build Canada's satellite broadcasting infrastructure, placing the NTV application in jeopardy after Power Corporation of Canada, a key investor in the plan, backed out.

Bruner and Hill's group, Global Communications, scaled back the original NTV proposal to a network of seven UHF transmitters in Southern Ontario, whose combined footprint would have provided at least secondary broadcast coverage from Montreal to Detroit.

Global Communications still aspired to eventually build out Soble's original 97-station network, and viewed the seven-transmitter Ontario chain as an interim step.

However, since CHCH was no longer involved in the application, Global's iteration of the plan also required the launch of a new station to serve as its flagship.

It branded itself as the "Global Television Network," a name which reflected its then-unprecedented coverage of most of Southern Ontario from six transmitters (a seventh that would have reached Montreal was turned down) fed from a centralized studio.

[3] Through its entire history, however, the station's main studio facility has been based in a converted factory (built 1954 for Barber Greene Canada Limited)[4] in the Don Mills area of North York (since 1998, located in Toronto).

It had made a serious blunder by signing on in the middle of the 1973–74 television season, and prospective advertisers did not have the money to spare for commercial spots.

[10] Trueman has noted in his memoir that the programme was groundbreaking: "Our newsroom-studio combination ... served as a model for the new CHAN-TV facilities in Vancouver, and it is currently [1979] the inspiration for Ted Turner's new Cablenews operation in Atlanta".

[11] The programme also pioneered the use of "regional correspondents," usually print or radio journalists, who would regularly advise the station about stories in their part of Ontario.

Other anchors on the station over the years have included Mike Anscombe, Beverly Thomson, John Dawe, Jane Gilbert, Peter Kent, Loretta Sullivan, Bob McAdorey, Thalia Assuras and Anne-Marie Mediwake.

From February to August 2009, CIII simulcast former Hamilton sister station CHCH-TV's Morning Live newscast each weekday from 7 to 9 a.m.

The CHCH simulcast was later dropped after Canwest sold that station to Channel Zero, with CIII airing second-run lifestyle programming in the morning timeslot, as well as rebroadcasts of the previous night's News Hour Final.

The expansions to CIII's news programming were part of a benefits package that was included as a condition of the sale of the Global Television Network to Shaw Communications.

[15] In June 2016, Global News announced that The Morning Show co-host Liza Fromer would not have her contract renewed after five years with the station.

It is therefore possible that the SD feed needed to be broadcast over-the-air in order to continue carriage of this dedicated feed on cable and satellite providers (however, it also served as a benefit to some over-the-air viewers with 4:3 television sets and digital converters, insofar as it allowed those viewers to avoid older 4:3 programs appearing both letterboxed and pillarboxed).

On April 10, 2012, Shaw Media applied for permission to change CIII-DT-6's allocation from VHF channel 6 to UHF channel 14, switching from circular to elliptical polarization, citing the VHF-Low band's impulse noise (compared to the VHF-High and UHF bands) causing reception issues, which would be mostly resolved with a higher frequency.

Shaw Media had begun applying for permission to convert its transmitters in Northern Ontario to digital, with CFGC-TV in Sudbury and CFGC-TV-2 in North Bay on June 14,[21] and CIII-TV-12 in Sault Ste.

The UHF signal would have a slightly smaller range of broadcast coverage, but Shaw had admitted that areas on the fringes would still be able to receive Global programming via CIII-DT-29, CIII-DT-41 and CIII-TV-4.

On December 4, 2020, the CRTC approved a request from Corus Entertainment to shut down CIII-DT-27 and CIII-TV-2 (among other Global retransmitters) in favour of multiplexing CIII-DT-27 via CHEX-DT and CIII-TV-2 via CKWS-DT Kingston.

[27] At the same time, in an attempt to disclaim competition with American outlets, Global ceased sending listings to Detroit's newspapers.

[30] In 1981, Global sought permission to build a higher-power successor to the Cottam station for the Windsor–Detroit market;[31] the CRTC denied this application in December of that year.

CHFD's owners, the Dougall family, were concerned about Global threatening their local television monopoly (Dougall Media controls all of the local network television output for the Thunder Bay region[40] and had previously lobbied the CRTC to cease CHCH-TV's cable transmissions in the mid-1990s[41]) and pressured the CRTC to deny Global's application to build a transmitter there.

Similarly, in Kenora, former CTV affiliate, CJBN-TV (which was owned by Shaw), switched to full-time Global programming in late 2011 (the station would cease operations in January 2017).