Park Overall stars as the title character, a single mother who moves from Knoxville to Philadelphia and tries to balance her job as a radio program host with parenting her teenage son Greg (Jesse Head).

Supporting characters include Katie's niece Liz Berlin (Ana Reeder) as well as her co-workers, played by Jay Thomas, Jim Rash, and Simon Rex.

The network initially optioned the show as a potential mid-season replacement for the 1998–1999 television season, but it was delayed for a year due to production issues.

[1] Katie first works for the Crescent Corset Company and later Car City, while her son attends Benjamin Franklin High School.

[2] Katie makes a positive first impression with WLBP-FM's general manager Glen Shotz (Jay Thomas) while trying to sell him a car.

"[4] Brooks and Marsh wrote Katie impressed Glen with her "perception, Southern wit, and strong opinions" and said she received a job to host a phone-in radio program because of her "out-spoken nature".

[2][6] Program director Mitchell Tuit (Jim Rash) dislikes her as he opposes a talk show airing on his primarily rock and roll station.

[7] When discussing these low ratings, The Washington Post columnist Lisa de Moraes wrote: "Maybe they should've let a couple of people know they were running it.

[24] Rob Owen, while writing for the Pittsburgh Post-Gazette, said Katie Joplin was scheduled for a "short run",[25] and Times Leader's Norma Cavazos described it as a "summer series".

[23] Prior to its debut, Katie Joplin was recommended by critics from TV Guide,[11] The News Journal,[37] The Arizona Republic,[38] and the South Florida Sun-Sentinel.

[40][41] David Bianculli, while writing for Fort Worth Star-Telegram, said both Katie Joplin and the CBS sitcom Thanks were not "deemed worthy of consideration for their respective networks' fall schedules".

Berman identified Northern Exposure and Melrose Place as successful instances of shows premiering in the summer, and criticized Katie Joplin as a failure because of its short run.

He criticized the show's premise, believing it was unrealistic for a middle-aged woman to be hired as a radio host without any prior experience.