The two stations share studios on West Adams Street in Downtown Phoenix; KSAZ-TV's transmitter is located atop South Mountain.

After switching affiliations to CBS in 1955, KOOL-TV rose to become Phoenix's highest-rated station under the ownership of Gene Autry and Tom Chauncey.

A falling-out between Autry and Chauncey ended with the sale of KOOL-TV to the Gulf United Corporation in 1982; separated from its sister radio properties, channel 10 changed its call sign to KTSP-TV.

Three months later, as part of the first act in a national realignment of network affiliations initiated by then-owner New World Communications, the station announced it would switch from CBS to Fox.

Coinciding with the switch to Fox was a major expansion of the station's news department, including new morning and prime time newscasts.

However, the three months of forced independent status and miscalculations around syndicated programming and new competitors caused the station's ratings to fall dramatically, with some newscasts losing half their viewership.

Fox acquired the New World stations in 1996 and steadied the struggling operation, bringing the newscasts more in line with the network's target audience and instituting a flashier style.

In July 1952, KOY (550 AM), the home of the Mutual Broadcasting System in Phoenix and one of the oldest stations in the state, filed its own bid.

The time-sharing proposal, first used by the FCC in television in grants for channel 10 in Rochester, New York, and suggested to KOOL and KOY by the commission,[5] was approved on May 27, 1953, with KOOL-TV and KOY-TV getting construction permits the same day.

[6] Even though the two stations would have separate staffs and ownership, much of the physical plant would be shared, including a maximum-power transmitter site on South Mountain.

KOY general manager Albert D. Johnson believed that the station would do better under one operator instead of two and stated that the goal of the shared-time venture—to avoid lengthy comparative hearings—had been met.

That May, Autry sued Chauncey, alleging that he had mismanaged the assets of KOOL Radio-Television, Inc., to the tune of millions of dollars and had diverted company funds to Arabian horses, cars, and airplanes.

[25] Chauncey then filed a countersuit, accusing Autry and Gulf of racketeering and trying to pressure longtime manager Homer Lane, who owned a small but pivotal stake in the firm, to sell.

[27] In the wake of the dueling lawsuits, and as early as November 1981, speculation began to circulate that Chauncey and Lane were nearing a sale of their stakes to Gulf.

[31] Homer Lane, the general manager and minority owner, was replaced by Jack Sander, hired from WTOL in Toledo, Ohio.

[20] Gulf also invested in new production equipment to give KTSP a more high-tech look,[32] and it completed a project started under Chauncey to replace the transmitter and tower on South Mountain.

[38] Other subsidiaries of Great American Communications Corporation filed for Chapter 11 bankruptcy in 1993, a move that did not affect the television and radio holdings.

[30] After emerging from bankruptcy, Great American Broadcasting (renamed Citicasters soon after[40]) put four of its stations (including KSAZ-TV) up for sale, seeking to raise money to pay down debt and fund more acquisitions in radio.

[41] KSAZ-TV, along with WDAF-TV in Kansas City, Missouri; WGHP in High Point, North Carolina; and WBRC in Birmingham, Alabama, were sold to New World Communications on May 5, 1994, for $360 million.

In the aftermath of the change, channel 10 management faced the task of melding the station's more mainstream image with the new Fox programming,[47] which proved difficult.

This status almost became short-lived: in February 1997, Fox nearly traded KSAZ and sister station KTBC in Austin, Texas, to the Belo Corporation in exchange for Seattle's KIRO-TV.

[53] Fox began to upgrade the station's programming, adding some high-rated off-network sitcoms (such as M*A*S*H, Seinfeld and King of the Hill) as well as higher-rated syndicated court and reality shows.

[59] The newsroom grew from six people when Close arrived to 23 by 1970, making it the largest among Phoenix's four news-producing stations;[60] a helicopter, the first of several, was also added to the KOOL arsenal at that time.

At one point, channel 10's dominance was so absolute that its 6 p.m. newscast (anchored by Close) attracted 46 percent of all TV households in the market, the same share as the CBS Evening News with Walter Cronkite.

[64] On May 28, 1982, at about 5 pm, Joseph Billie Gwin, wanting to "prevent World War III", forced his way into the KOOL-TV studios and fired a shot from his gun.

However, in the late 1980s, after KTVK poached Miller and Alvidrez, channel 10's news ratings began to decline, not helped by a series of unforced errors.

In 1989, KTSP newscaster Shelly Jamison left the station after appearing as both a cover model and posing nude in a Playboy pictorial.

[69] The most publicized move, however, was the 1991 dismissal of anchor Karen Carns, who found out she had been fired 15 minutes before the evening newscast when a newspaper reporter called to get her reaction.

She told the San Francisco Examiner that the station practiced "crime and body-bag journalism, just like Miami" and that she "watched the destruction of a once-fine newsroom" at channel 10.

Three subchannels on the multiplex are hosted for KASW, Phoenix's ATSC 3.0 (NextGen TV) station, which in turn broadcasts KSAZ in that format.