KXII's signal is relayed on low-power translator station KXIP-LD (channel 12) in Paris, Texas (in the Dallas–Fort Worth television market), and also on the second and third subchannels of KAQI-LD.

After the family filed an application with the Federal Communications Commission (FCC) for the construction permit in 1954, the Reisen-Easleys obtained VHF channel 12 for their proposed television station after negotiating with Eastern Oklahoma Television, Inc., owner of Ada-based competitor KTEN (channel 10), for the allocation (the FCC had reassigned the channel 12 allocation to the Sherman–Ada market following the issuance of the Sixth Report and Order in 1952, in which the agency moved the same assignment from Waco to Abilene, Texas, where it would become occupied by present-day ABC affiliate KTXS-TV, to avoid interference with the Sherman-Ada frequency).

On April 2, 1957, the station's 360 feet (110 m) transmission tower was felled by a strong tornado (later retroactively rated as an F2) that touched down west of Dougherty and hit portions of northern Carter County, Oklahoma.

Transmitter engineer Chester Rollins was near the tower at the time the tornado hit and escaped serious injury, despite the transmission building he was in losing its roof.

In late 1958, the Riesen family sold KVSO-TV to Texoma Broadcasting, a holding company owned by businessman Milford N. "Buddy" Bostick, who founded fellow CBS affiliate KWTX-TV in Waco, Texas three years earlier (The Daily Ardmoreite remained under the Riesens' ownership until 1983, when they sold the newspaper to Stauffer Communications).

During the 1960s and early 1970s, most CBS programming was fed to cable subscribers in the Texoma area via the network's affiliates in surrounding markets, including KWTV in Oklahoma City, KAUZ-TV in Wichita Falls, and KRLD-TV (now Fox owned-and-operated station KDFW) in Dallas–Fort Worth.

As a result, viewers living in and surrounding areas of south-central Oklahoma located within a 25-mile (40 km) radius of the KXII transmitter (including the cities of Ardmore, Madill and Durant) experienced fair to poor reception of KTEN.

In turn, channel 10 had marginal if not non-existent coverage in some adjoining areas of north-central Texas (including Sherman, Denison and Gainesville) that were able to receive KXII.

This turned channel 12 into a hybrid station that carried almost half of NBC and CBS' respective programming inventories for the next few years.

The station successfully petitioned the FCC to change its city of license from Ardmore to Sherman in 1992; this was done primarily to allow Grayson County to be classified as in its market for the first time in its history, taking it from the 178th-largest area of dominant influence to the 157th-largest.

Through the transaction, which was finalized on October 1, 1999, Gray paid $41.5 million in cash as well as additional cash payments for certain accounts receivable to purchase channel 12 from Bostick-owned KXII Broadcasters Inc.[10][11][12][13][14][15] KXII was one of the few remaining commercial broadcast television outlets in the United States as well as the last major network affiliate station in Oklahoma and Texas to sign off the air during the overnight hours, occurring on Saturday nights/early Sunday mornings from 2:05 to 5 a.m.

The station carried most regional or national Cowboys game telecasts aired by CBS until its contractual rights to the National Football Conference (NFC) concluded in 1993 (the team's over-the-air game telecasts aired locally on KTEN during that station's tenure as a part-time Fox affiliate from 1994 to 1998).

Because of KXII's status as the only major-network affiliate licensed to a city on the Texas side of the Sherman–Ada market, the balance of the stories featured on the station's newscasts tend to lean toward those affecting Sherman, Denison and surrounding areas of north-central Texas, albeit with a nearly equal focus on stories occurring in south-central Oklahoma.

Debuting as an hour-long broadcast from 6 to 7 a.m., the program—which debuted ten years after KTEN debuted its own morning show, Mornin' Cup (now KTEN News Today)—expanded to 90 minutes (starting at 5:30 a.m.) in January 2006, with an extra five minutes being added to the program two years later following the retirement of longtime anchor Norman Bennett; the morning newscast was retitled News 12 AM in 2013, at which point it expanded into a two-hour broadcast at 5 a.m. On September 18, 2006, KXII debuted a new set for its newscasts designed by San Diego–based FX Group, which replaced a set that had previously been in use by the station since 1995 (the set, which also includes separate areas for sports specials and segments as well as an update desk for breaking news alerts, was updated with new duratrans in November 2015, at which point the station also began using new cuts from its existing music package, Gari Media Group's "The CBS Enforcer Music Collection").

On April 20, 2010, KXII became the first television station in the Ada–Sherman market (and the third station in Oklahoma, behind KFOR-TV in Oklahoma City and KJRH-TV in Tulsa) to begin broadcasting its local newscasts in high definition; the KXII-DT3 newscast was included in the upgrade, which saw cameras and broadcast equipment at the Sherman and Ardmore studios being upgraded to allow the gathering, production and dissemination of high-definition video content.

Subsequently, on April 29, 2013, KXII began producing an hour-long weekday morning newscast at 7 a.m., titled News 12 Good Day, which competed against CBS This Morning on the station's main channel (Good Day was canceled in September 2015 due to low viewership, with KXII-DT3 concurrently adding a simulcast of News 12 AM).

[24][25][26] KXII discontinued regular programming on its analog signal, over VHF channel 12, on February 6, 2009,[27] two weeks prior to the original target date on which full-power television stations in the United States were to transition from analog to digital broadcasts under federal mandate (which a Congressional resolution later delayed to June 12, in order to allow additional time for viewers reliant on over-the-air television service to obtain digital tuning equipment).