It was founded by Stanley Weston, long-time publisher of numerous boxing and pro wrestling titles.
KO Magazine, nicknamed "The Knockout Boxing Magazine", ran some popular features, such as a round-by-round section where the most important fights were described punch by punch, posters with the boxer's complete records on the back, and a question and answer interview section.
Other key staff members included Steven Farhood, Richard Countis, Stu Saks, Jeff Ryan, Bill Apter and Ken Morgan.
Contributing writers included long-time boxing reporters Al Bernstein and Richard Hoffer.
Each issue also included letters from fans ("Between Rounds"), a color centerfold and an "International Report" which featured match results from around the world.