WVIT signed on for the first time on February 13, 1953 as WKNB-TV, owned by the New Britain Broadcasting Company along with WKNB radio (840 AM, now WRYM). The calls stood for Kensington-New Britain. It is Connecticut's second-oldest television station, and the first on the UHF band. It has been an NBC affiliate for nearly all of its history. However during its first two and a half years, it carried CBS programming.

In 1954, only a year after channel 30 signed on, Hartford and New Haven were combined into a single television market. However, WKNB's signal was not strong enough to cover southern Connecticut at the time - a problem that would hamper channel 30 for almost a quarter-century. As a result, a few CBS programs continued to be seen in the market on New Haven's WNHC-TV (channel 8, now WTNH) for another year due to this shortfall in channel 30's coverage. In 1955, WKNB dropped CBS and became a primary NBC affiliate. Well into the 1960s, many viewers northeast of Hartford used outdoor VHF antennas to watch NBC programming via WBZ-TV in Boston or WJAR in Providence, while viewers southwest of Hartford with outdoor TV antennas received NBC via network flagship WRCA-TV (now WNBC) in New York City; reception was often spotty.

NBC itself purchased the WKNB stations in December 1956, and renamed channel 30 WNBC (for New Britain, Connecticut) a month later. It planned to boost the station's signal to cover all of the market, but these plans never materialized. In its first stint as an NBC-owned station, channel 30 failed to gain much headway in the ratings, largely because television manufacturers were not required to include UHF tuning capability until 1964. Viewers had to buy an expensive converter to watch WNBC, and even with one the picture was barely viewable. Nonetheless, NBC bought channel 30 as part of an experiment to determine whether UHF could be competitive with VHF.

In September 1957, the Hartford-based Travelers Insurance Company signed on independent station WTIC-TV (channel 3, now WFSB), the state's second and last VHF station. Within a year of its debut (and despite its radio sister having been an NBC radio affiliate for over thirty years) WTIC-TV became Connecticut's CBS affiliate, replacing its owned-and-operated station, WHCT-TV (channel 18, now WUVN). NBC then realized its UHF experiment was a lost cause and in June 1959 sold WNBC to Plains Television, a joint venture of Transcontinental Properties and H & E Balaban Corporation (WKNB radio was also included in the sale, but was spun off immediately afterward).

As part of the deal, Springfield Television, the owner of fellow NBC affiliate WWLP in Springfield, Massachusetts, was to have held a one-third stake in channel 30; it abandoned this stake before the deal's completion after concerns arose over their overlapping coverage areas, but continued to hold an option to reacquire it for some time afterward. In 1960, the calls changed again – this time to WHNB-TV (for Hartford-New Britain). This change came because NBC wanted the WNBC calls for its flagship radio and television combination in New York City.

In 1966, WHNB-TV became, once again, one of two NBC affiliates in Connecticut; the network signed with Waterbury-licensed WATR-TV (channel 20) in order to get its programming into New Haven on a strong signal. By this time, television manufacturers were now required to include all-channel tuning. Channel 30 itself made up for the shortfall in its market coverage by operating two low-power translators (starting in 1971): W79AI (channel 79) in Torrington and W59AA (channel 59) in New Haven.

Later years

Plains Television sold WHNB-TV to the original Viacom in 1978, and the station's call letters were changed on July 17 to WVIT (for "Viacom International Television") to reflect its new ownership. Viacom immediately announced plans to boost WVIT's signal to cover all of the market. In 1980, channel 30 signed on with a new transmitter that more than doubled its coverage area, giving it a clear signal to much of New Haven for the first time, though the channel 59 repeater was kept in service. WVIT became the market's sole NBC affiliate in March 1982, when WATR-TV's affiliation contract with NBC ended and the station became independent WTXX (it is now WCCT-TV). The Torrington translator was turned off in 1987, and the New Haven repeater was shut down in the middle 1990s to allow full-powered WTVU (now WCTX) to begin operations.

Viacom purchased Paramount Pictures in 1994, and all of Viacom's stations became part of the Paramount Stations Group. Within the next year, following the launch of the United Paramount Network venture it co-owned with Chris-Craft Industries, Paramount/Viacom began to sell off its non-UPN affiliated stations. WVIT, which was Viacom's first station purchase in 1978, ended up being the last non-UPN outlet sold in 1997. As part of a three-way deal, which closed on December 8 of that year, WVIT was sold to former owner NBC, while Paramount/Viacom ended up with WLWC in Providence, Rhode Island and WWHO in Columbus, Ohio, two stations owned by Fant Broadcasting which NBC operated by way of local marketing agreements.

In August 2007, plans were finalized to begin construction of a new high-definition and "green" studio facility on the same plot of land as the station's old studios, which had been in use since the station's inception. Ground was broken in October 2007, and construction was completed in Summer 2009. On July 16, 2009, WVIT moved into the new facility (the old facility was later demolished), and rebranded from NBC 30 to NBC Connecticut HD.

Analog-to-digital conversion

WVIT shut down its analog signal, over UHF channel 30, on June 12, 2009, as part of the federally mandated transition from analog to digital television. The station's digital signal relocated from its pre-transition UHF channel 55 to its former UHF analog channel 40, as its original digital channel was among the high band UHF channels (52-69) that were removed from broadcasting use as a result of the transition, using PSIP to display WVIT's virtual channel as 30 on digital television receivers. With the transition, height of the station's transmitter tower was increased to 2,030 feet.

News operation

WVIT presently broadcasts 34 and half hours of locally produced newscasts each week (with 5 and half hours on weekdays and 3 and half hours each on Saturdays and Sundays).

Under the ownership of Viacom, the company beefed up WVIT's news operation, which had long been an also-ran behind WFSB and WTNH due to its weak signal in New Haven. After the signal boost, it became a factor in the ratings for the first time in decades.