From 1956 to 1959, WITI used the Du Mont Vitascan color system—which required a completely darkened set with a single strobe light, causing eye strain—for its locally produced programs.
The station first signed on the air on May 21, 1956, operating as an independent station; it was originally owned by Independent Television, Inc., to whom the channel 6 construction permit was granted by the Federal Communications Commission (FCC) on June 11, 1955.
The station was originally licensed to the North Shore village of Whitefish Bay on a technicality in order to address short-spacing concerns with Davenport, Iowa station WOC-TV (now KWQC-TV, which also broadcast on channel 6) before the FCC fully finessed spacing among television station signals in different markets.
Notably the station is the only one in the market never to hold the local broadcast rights for Milwaukee Brewers baseball coverage, though the team has appeared since 1990 on the station through Major League Baseball's national contracts with CBS and now Fox.
In the fall of 1995, WITI dropped its longtime branding as "TV-6" (which it adopted in 1974 as an ABC affiliate) and began branding itself as "Six is News", in order to emphasize the station's newly expanded news schedule.
The market's original Fox affiliate, WCGV, briefly became an independent station before affiliating with UPN in January 1995.
The switch allowed WITI to retain its status as Milwaukee's "home" station for the Green Bay Packers.
On August 8, 1958, Storer Broadcasting purchased WITI in hopes of affiliating the station with CBS.
Storer had very good relations with CBS; company founder George Storer was a member of the CBS board, and most of its stations were CBS affiliates.
The network concluded it was better to have its programming on a VHF station, even if it was only an affiliate.
CBS sold WXIX to Cream City Broadcasting president Gene Posner; WITI-TV then began its first stint as a CBS affiliate on April 1, 1959.
In October 1956, the station affiliated with the NTA Film Network, which provided the station with 52 films from the 20th Century Fox library and syndicated programs.