In the title, "K.O" is a boxing term short for "Knock Out," when a fighter has hit his opponent so hard he hits the mat and cannot get up again before the count of 10.
This is the first time that Lucille Ball acted on television not playing Lucy Ricardo. Lucille Ball was supposed to do several more non-Lucy Ricardo roles on the series, but this was the only one that ever materialized.
Quinn Martin (Producer / Story) was married to "Lucy" writer Madelyn Pugh Davis from 1955 to 1960.
A country boy out of his element, Harold Tibbetts (Aldo Ray) is reminiscent of when Tennessee Ernie Ford visited the Ricardos on "I Love Lucy." Like Cousin Ernie, Harold has an enormous appetite and can't return home because he has no money. He also tends to speak with homespun wit.
"K.O. Kitty" most closely resembles a 1967 episode of "The Lucy Show" titled "Lucy, the Fight Manager" (S5;E20) starring Don Rickles as a washed-up boxer named Eddie who Lucy Carmichael decides to train at home. Lucy dubs herself 'Killer Carmichael' and even jumps rope in tandem with Eddie, a stunt she learned to do for "K.O. Kitty." Despite being by different writers, both scripts contain characters named Louis.