The early history of television in the United States, particularly between 1956 and 1986, was dominated by the Big Three television networks: NBC, CBS, and ABC. The term fourth television network was used within the industry during this era to refer to a theoretical fourth commercial broadcast (over-the-air) television network that would operate as a direct competitor to the "Big Three".

Prior to 1956, the DuMont Television Network operated as an existing fourth network alongside ABC, CBS, and NBC, but an inability to find solid financial ground, a weaker affiliate base, and internal competition from co-owner Paramount Pictures all contributed to DuMont's closure. Multiple companies, film studios and television station owners all either considered, announced or launched networks or program services that aspired to be the "fourth network", but none succeeded. Several of these attempts never advanced from being niche program services, while others either failed to launch or failed after launching. General consensus within the industry and by television critics was that a fourth television network was impossible; one television critic wrote, "Industry talk about a possible full-time, full-service, commercial network structured like the existing big three, ABC, CBS and NBC, pops up much more often than the fictitious town of Brigadoon." Non-commercial educational television, especially with stations aligned with National Educational Television and successor PBS, also found success as program services with network-capable functions.

The launch of Fox in October 1986 was met with ridicule; despite industry skepticism and initial instability, the network eventually proved profitable by the early 1990s, secured rights to NFL football in 1993 and initiated a major affiliate realignment the following year. Fox became the first successful fourth network, eventually surpassing the Big Three networks in demographics and overall ratings between 2004 to 2012, and again between 2020 to 2021.

Background

In the 1940s, four television networks began operations by linking local television stations together via AT&T's coaxial cable telephone network. These links allowed stations to share television programs across great distances, and allowed advertisers to air commercial advertisements nationally. Local stations became affiliates of one or more of the four networks, depending on the number of licensed stations within a given media market in this early era of television broadcasting. These four networks – the National Broadcasting Company (NBC), the Columbia Broadcasting System (CBS), the American Broadcasting Company (ABC), and the DuMont Television Network (DuMont) – would be the only full-time television networks during the 1940s and 1950s, as in 1948, the Federal Communications Commission (FCC) suspended approvals for new station construction permits. Although other companies – including Paramount Pictures (with the Paramount Television Network) – announced network plans or began limited network operations, these companies withdrew from television after the first few years, or in the Paramount Television Network's case the service withered through attrition over the same span as did DuMont's, losing most of its programming by 1953 and ceasing operations in 1956.

The FCC's "freeze," as it was called, was supposed to last for six months. When it was lifted after four years in 1952, there were only four full-time television networks. The FCC would only license three local VHF stations in most U.S. television markets. A fourth station, the FCC ruled, would have to broadcast on the UHF band. Hundreds of new UHF stations began operations, but many of these stations quickly folded because television set manufacturers were not required to include a built-in UHF tuner until 1964 as part of the All-Channel Act. Most viewers could not receive UHF stations, and most advertisers would not advertise on stations which few could view. Without the advertising revenue enjoyed by the VHF stations, many UHF station owners either returned their station licenses to the FCC, attempted to trade licenses with educational stations on VHF, attempted to purchase a VHF station in a nearby market to move into theirs, or cut operating costs in attempts to stay in business .

Since there were four networks but only three VHF stations in most major U.S. cities, one network would be forced to broadcast on a UHF outlet with a limited audience. NBC and CBS had been the larger networks, and the most successful broadcasters in radio. As they began bringing their popular radio programs and stars into the television medium, they sought – and attracted – the most profitable VHF television stations. In many areas, ABC and DuMont were left with undesirable UHF stations, or were forced to affiliate with NBC or CBS stations on a part-time basis. Although ABC had a radio network on which to draw affiliate loyalty and revenue, it was only a fraction the size of NBC and CBS. As a result, it was near bankruptcy in 1952. DuMont, without a radio network as a lifeline, was unprofitable after 1953.

A fatal blow was struck in 1953 when ABC merged with Paramount's former theater chain, United Paramount Theaters. The deal gave ABC a badly-needed cash infusion, and at least on paper gave it the wherewithal to offer a national service on the scale of CBS and NBC.

DuMont realized the situation was untenable. However, when Paramount vetoed a merger offer from ABC, DuMont announced in April 1955 that all remaining scripted programming would be dropped by September, effectively ending regular operations; the network's former owned-station group (WABD and WTTG) was spun off later that year as DuMont Broadcasting. The end of DuMont allowed ABC to experience a profit increase of 40 percent that year, although ABC would not reach parity with NBC and CBS until the 1970s. The end of DuMont left many UHF stations without a reliable source of programming, and many were left to become independent stations. Several new television companies were formed through the years in failed attempts to band these stations together in a new fourth network.

Timelines

Rationale Some within the industry felt there was a need for a fourth network; that complaints about diversity in programming could be addressed by adding another network. "We need a fourth, a fifth, and a sixth network," one broadcaster stated. While critics rejected "the nightly tripe being offered [to] the public on the three major networks," they were skeptical that a fourth network would offer better material: "[O]ne wonders if a new network lacking the big money already being spread three ways will be able to come up with tripe that is equal. Certainly a new network is not going to stress quality programming when the ratings indicate that the American public prefer hillbillies, cowboys and spies. A new network will have to deliver an audience if it is to attract the big spenders from the ranks of sponsors."

Advertisers, too, called for the creation of a fourth network. Representatives from Procter & Gamble and General Foods, two of the largest advertisers in the U.S., hoped the competition from a fourth network would lower advertising rates on the Big Three. Independent television producers, too, called for a fourth network after battles with the Big Three.

Unfulfilled attempts George Fox Organization network George Fox, the president of the George Fox Organization, announced tentative plans for a television film network in May 1956. The plan was to sign 45 to 50 affiliate stations; each of these stations would have input in deciding what programs the network would air. Four initial programs – Jack for Jill, I'm the Champ, Answer Me This, and It's a Living – were slated to be broadcast; the programs would be filmed in Hollywood. However, only 17 stations had agreed to affiliate in May. The film network never made it off the ground, and none of the planned programs aired.

Mutual Television Network

The Mutual Broadcasting System (Mutual), established as a cooperative radio network owned by the affiliates, showed varied interest in a television counterpart. During the network's annual shareholder meeting on April 1950, network president Frank White announced the tentative formation of the "Mutual Television Network" comprising stations in New York (WOR-TV), Los Angeles (KHJ-TV), Chicago (WGN-TV), Boston (WNAC-TV) and Washington, D.C. (WOIC), all television adjuncts of existing network affiliates. A sixth station in Pittsburgh was proposed, but its originating radio station failed to gain a TV license. The 5-station attempt would fail in short time. When General Teleradio de facto became the network's owner in 1951 by acquiring all but one of the network's largest affiliates, General Tire president Thomas F. O'Neil started putting a potential Mutual all-movie network together. Mutual purchased a large group of English films and paid $1.5 million for the right of unlimited play for two years of Roy Rogers and Gene Autry westerns.

NTA Film Network

On October 15, 1956, National Telefilm Associates launched the NTA Film Network, a syndication service that distributed both films and television programs to independent television stations and stations affiliated with NBC, CBS or ABC; the network had signed agreements with over 100 affiliate stations. The ad hoc network's flagship station was WNTA-TV (channel 13) in New York City. The NTA Network was launched as a "fourth TV network," and trade papers of the time referred to it as a new television network. Despite this effort, by 1961, NTA carried a significant debt load and WNTA-TV was losing money against stiff competition from independent stations WNEW-TV and WOR-TV.

After being placed on the market, WNTA was sold to the Educational Broadcasting Corporation and relaunched the following year as non-commercial station WNDT, aligned with National Educational Television (NET).. National Telefilm Associates continued syndication services for stations for several years after the closure of NTA Film Network, with Divorce Court was seen as late as 1969.

Pat Weaver Pat Weaver, a former president of NBC, twice attempted to launch his own television network; daughter Sigourney Weaver once said, "it was always his dream to transform television." According to one source, the network would have been called the Pat Weaver Prime Time Network. Although the new network was announced, no programs were ever produced.

Unisphere/Mizlou

In mid-1965, radio businessman Vincent C. Piano proposed the Unisphere Broadcasting System. The service would have operated for 2½ hours each night. However, Piano had difficulty signing affiliates; a year later, no launch date had been set, and the network still lacked a "respectable number of affiliates in major markets."

The network finally launched under the name Mizlou Television Network in 1968, but the concept had changed. Like the Hughes Network, Mizlou only carried occasional sporting and special events. Despite developing a sophisticated microwave and landline broadcasting system, the company never developed into a major television network.

United Network