The City of New York, which was one of the United States' first municipalities to enter into broadcasting with the 1924 sign-on of WNYC radio, was granted a construction permit to build a new commercial television station in 1954. Seven years later, on November 5, 1961, WUHF took to the air for the first time. Through the Municipal Broadcasting System, which held the channel 31 license, the City (led by then-mayor Robert F. Wagner, Jr.) and the Federal Communications Commission (FCC) used WUHF as an experiment to determine the viability of ultra-high frequency (UHF) broadcasts within an urban environment. Some of the early programming on WUHF included simulcasts of New York's existing commercial VHF stations; educational films produced by WNYC's Television Film Unit, established in 1949; college-level distance learning telecourses; and, reportedly, a nightly rundown of the New York City Police Department's "wanted" criminals list. The experiment was carried out through the installation of UHF receivers in several hundred test homes, public schools and businesses, with reception monitored by FCC and City engineers.

After a year of test broadcasting was deemed successful, full control of WUHF was then transferred to the City. The station became a full-time operation on November 5, 1962, with new call letters WNYC-TV to match its sister radio stations WNYC (then at 830 AM and now at 820 AM) and WNYC-FM (93.9 MHz). Though the channel 31 license was classified as commercial, WNYC-TV was operated as a non-commercial station. Some of the programming from the experimental period continued, and now included live broadcasts of the United Nations' General Assembly meetings. As a municipally-owned station, WNYC-TV also devoted airtime to shows focused on civic affairs, along with other public-interest programs. The station also carried some programming from National Educational Television (NET) and its successor, the Public Broadcasting Service (PBS), but later increasingly ran more independent educational television programs. For many years WNYC-TV ran a 15-minute newscast on weekdays, called News from City Hall (later called News City and expanded to 30 minutes), highlighting the day's events in municipal government.

During its years of City ownership, WPXN-TV was housed in the Manhattan Municipal Building, located across from New York's City Hall. In 1979, Mayor Ed Koch considered selling the WNYC stations to other interests due to a municipal fiscal crisis. Instead, the WNYC Foundation was established as an outlet to raise operating capital for the stations. Though there were bi-annual fundraising appeals made by the WNYC stations, WNYC-TV did not run on-air pledge drives in a manner similar to other PBS stations, mostly because it was a commercial licensee. It would not, however, have faced any problems had it done so, as WNED-TV in Buffalo, New York operated for decades as a non-commercial broadcaster under a commercial license.

Channel 31 also leased blocks of airtime to foreign-language broadcasters. In the 1980s, among the largest providers of foreign programming were Japan's Fujisankei Communications Group, which aired a morning show on weekdays, and RAI, the Italian public broadcaster which programmed two hours on weeknights, and five hours on Sunday mornings, a period which included airings of Italian soccer games.

Also during this era, WNYC-TV joined the music video phenomenon – and in the process contributed to the growth of hip hop culture and rap music. In the summer of 1983, channel 31 premiered the hour-long Video Music Box, created by station employee Ralph McDaniels. The program started off with an eclectic selection of videos from pop, rock, and rhythm-and-blues artists. Rap music was also included, but eventually the program became exclusive to the rap and R&B genres. Video Music Box served as a launching pad for many rap music artists, and was said to have been the basis behind MTV creating Yo! MTV Raps several years later. Video Music Box would remain prominently on WNYC-TV's schedule for the next decade (the show now airs on WNYE-TV).

Transition into private ownership

Shortly after becoming mayor in 1994, Rudolph W. Giuliani disclosed that he was considering selling the WNYC stations. Giuliani believed that broadcasting was no longer essential as a municipal entity, and that any financial compensation would be used to help the City cover budget shortfalls. The final decision was made in March 1995: the WNYC radio stations would be sold to the WNYC Foundation, while the City opted to solicit separate bids for WNYC-TV through a blind auction.

A partnership of Dow Jones and Company and ITT Corporation won the WNYC-TV auction with a bid of $207 million, which at the time was the largest price ever paid for a UHF television station. The sale of channel 31 to commercial interests had many detractors. Foreign broadcasters complained, as they now found themselves without an outlet for their programming, and individual financial contributors criticized the Giuliani administration for selling the station to the highest commercial bidder, rather than to the WNYC Foundation. The foreign producers found new outlets through WNYE-TV, Newton, New Jersey-based WMBC-TV, and the City-owned Crosswalks cable TV network (now nyctv).

The sale took nearly a year to become official, and on Midnight, June 30, 1996, WNYC-TV signed off for the final time. Twelve hours later, at Noon on July 1, channel 31 reappeared as WBIS-TV (branded as S+), carrying programming from the Classic Sports Network most of the day, and infomercials in overnights. Meanwhile, Dow Jones and ITT worked on their planned permanent format for WBIS, which would offer business news during the day and professional sports news and games at night. The new format would launch in January 1997, with business news from Dow Jones (anchored by New York news veteran Tony Guida) running from 6 am to 6 pm and sports programming running from 6 pm to 6 am. ITT, then co-owners of Madison Square Garden (and the teams that played in the venue) with Cablevision, offered the team coverage with the New York Knicks and New York Rangers. WBIS-TV was also slated to carry some games of the New York Islanders, New Jersey Devils, and New Jersey Nets (all of which aired on Cablevision-owned SportsChannel New York), and in fact did air at least one game from each of the three teams. Some Classic Sports Network programming remained on weekends and on evenings when there was no live sports coverage, and infomercials continued in overnights. There was some talk that WBIS would secure broadcast rights for the New York Yankees, but that team opted to remain with WPIX for the 1997 season. It also aired a large amount of programming from Fox Sports Net, such as Big 12 Conference and Pacific-10 Conference sports, weekly Thursday night baseball games, and Fox Sports News (since at the time FSN didn't have an outlet in New York), as well as shows from the then young Outdoor Life Network and Speedvision networks on weekends.

The WBIS hybrid format, though ambitious, was a complete dud as the station failed to attract both viewers or advertising revenue. In May 1997, ITT sold its share of the station, as well as its half of Madison Square Garden, in an effort to resist a hostile takeover attempt by the Hilton Hotels Corporation. Dow Jones continued to run the station alone, but within weeks decided it could no longer support the losses and looked to sell out. Paxson Communications, which owned several UHF stations nationwide, purchased WBIS for $225 million, topping the 1995 sale price by $18 million.

The hybrid format was taken off the air in June, though reruns of WBIS' business programming, some Fox Sports programming, and documentaries from the CBS cable presence "Eye on People" ran in the interim. Paxson took control of the station in August, renaming it as WPXN-TV, and ran channel 31 under a local marketing agreement with a format that featured Bloomberg Business News in daytime, infomercials (from Paxson's inTV) and religious programs (from Paxson's Worship Network) the rest of the day. The LMA was necessary as Paxson was seeking FCC permission to temporarily keep both WPXN and WHAI-TV (channel 43) in Bridgeport, Connecticut. The FCC eventually granted Paxson a temporary waiver for the purchase of WPXN, which closed on March 6, 1998. A year later, Paxson sold the Bridgeport station to other interests.

On August 31, 1998, WPXN, along with the rest of the Paxson stations, premiered the new Pax television network, with a programming mix of infomercials, off-network reruns labeled as "family entertainment", and the Worship Network during overnights. NBC purchased a 32 percent stake in Pax in 1999, and as part of the deal NBC encouraged its stations, both owned and affiliated, to enter into joint sales agreements with the local Pax outlet. In New York, WNBC-TV did just that with WPXN, and as a result channel 31 aired rebroadcasts of WNBC-TV's evening newscasts. The LMA arrangements ended in July 2005, though NBC retains its ownership share in the network to the present day.

On September 11, 2001, the transmitter facilities of channel 31, as well as six other New York City television stations and several radio stations, were destroyed when two hijacked airplanes crashed into and destroyed the World Trade Center towers. When WPXN-TV returned to the air days later, channel 31 was broadcasting at low power from a temporary facility in West Orange, New Jersey. It has since moved its transmitter to the Empire State Building.

In July 2005, Pax TV changed its name to "i", and on January 29, 2007, the network became ION Television. Like most Ion stations, WPXN then ran infomercials until 6 pm daily, except for some religious shows on weekday mornings and Sunday mornings, along with some educational shows from qubo on Friday afternoons, and Ion's collection of mostly-off-network reruns filling the primetime portion of the schedule plus one public affairs show, ION New York City.

Repeaters

WPXU-LD, channel 12 in Amityville, New York, relays WPXN-TV. This service began operation on or about May 2, 2011. It replaced WPXU-LP, an analog station on channel 38 that went dark some years earlier after its channel was reallocated to the digital signal of WWOR-TV. On December 15, 2014, Ion reached a deal to donate WPXU-LD to Word of God Fellowship, parent company of the Daystar network.

WPXO-LP, channel 34 in East Orange, New Jersey, relayed WPXN-TV until it was sold in August 2007. It is now an affiliate of Spanish-language network MundoMax.

Analog-to-digital conversion