KBZK was founded in September 1987 as KCTZ, and was originally Bozeman's ABC affiliate. The station's original owner, Bee Broadcasting Associates, agreed to sell KCTZ to Big Horn Communications shortly afterward (an earlier attempt by Eagle Communications, owner of KECI-TV, to acquire the station and operate it as a satellite of KECI had been denied by the Federal Communications Commission in January 1987); in its early years, channel 7 largely carried the same programming as KOUS-TV (channel 4, now KHMT) in Billings, and station identifications mentioned KCTZ alongside KOUS and its Miles City satellite, KYUS-TV. The sale to Big Horn was completed November 16, 1988.