The station signed on for the first time on May 15, 1954, as KGLO-TV, owned by Lee Enterprises along with the Globe Gazette and KGLO radio (1300 AM and 101.1 FM).

KIMT's digital signal on UHF channel 42 launched in May 2002 and added high definition capabilities from the network during that summer.

On April 6, 2006, Media General announced it would sell KIMT as part of the company's acquisition of four NBC owned-and-operated stations.

[3] On August 2, New Vision Television made public it had bought KIMT and sister station WIAT in Birmingham, Alabama, for $35 million.

[5] After the transition (which occurred at 12:12 p.m.), KIMT planned to continue using digital channel 42 and filed paperwork with the FCC to eventually increase that signal's output power from 200 to 800 kW which would more effectively fill its coverage footprint.

[8] The merger was completed on December 19, making KIMT a Media General property once again, and marking the third ownership change for the station in less than a decade.

[9] In September 2015, Media General announced the acquisition of Meredith Corporation in a cash and stock deal valued at $2.4 billion.

[13] On October 1, 2019, Allen Media Broadcasting, a subsidiary of Entertainment Studios, announced that it would acquire KIMT and 10 other Heartland stations for $290 million.

On March 20, 2011, rival NBC affiliate KTTC (channel 10) in Rochester upgraded its local news to full high definition becoming the first outlet to do so.