Originally under the ownership of the Fighting and Entertainment Group (FEG), K-1 was considered to be the largest Kickboxing organization in the world.

Nevertheless, some reports suggest that it represents the initial K found in competing disciplines such as karate, kickboxing, kung fu, kempo, kakutougi (the generic Japanese term for "combat sports"), and taekwondo.

[7] Another theory claims that the K simply comes from kakutougi and the "1" component pertains to the single weight division (in earlier competition) and the champion's unique position.

[14] In early 2011, FEG publicly announced that they were facing financial problems and that the organization would take some months off to restructure.

Many fighters and managers spoke out against FEG, due to unpaid fight purses, as well as objections to the direction that its owner was taking K-1.

[15] The entire K-1 brand, along with most of its trademarks, with the exception of, 'K-1 Koshien', 'K-1 MAX' and 'Dream', were sold to Japanese real estate firm, Barbizon Corporation Limited, on July 28, 2011.

[17] In March 2012, It's Showtime announced that EMCOM Entertainment established a new company K-1 Global Holdings Ltd. in Hong Kong.

After the event, controversy and rumors circulated over fighters not being paid for their performances, unpaid financial obligations of FEG, and the incomplete transfer of ownership of the K-1 name.

[23] Though the agreement would eventually end, SK president Eduard Irimia stated that while its company will be independent in 2013 it will still continue to have cooperation with any interested promotion, including K-1, by offering fighters.

It was seen at the time as the second tier of K-1 competition,[28] and produced a number of future K-1 fighters such as Takeru Segawa, Tatsuya Tsubakihara and Leona Pettas, among others.

[32] On December 17, 2018, it was announced that the former Krush and K-1 commentator and martial arts writer Takumi Nakamura would replace Mitsuru Miyata as the executive producer.

[35] On February 10, 2023, K-1 agreed on a mutual exchange of fighters with fellow Japanese promotion RISE,[36][37] after they successfully co-promoted the Tenshin Nasukawa vs. Takeru crossover pay-per-view event, known as "THE MATCH 2022".

[38] On February 28, 2023, M-1 Sports Media acquired the global licensing rights for the K-1 brand, which was from that point forward managed by K-1 International Federation (KIF).

By 1998, K-1 introduced the K-1 World Grand Prix format composed of K-1 Regional Elimination Tournaments (theoretically amounting to six), which qualify fighters for the K-1 World Grand Prix Final, along with licensed K-1 Fighting Network events designed to hold national preliminaries for regional qualification.

K-1's popularity differs greatly among six K-1 regions, which may limit the number of actual elimination tournaments or change locations.

[49] The promotion regularly uploads full fights, press conferences, and general media to its global YouTube channel.