K is an original anime project (not based on a pre-existing manga or novel) created by GoRA, a masked collective of seven writers, with the tagline 'Kizuna' (Bond).

The animation production was handled by GoHands, the studio also known for the TV anime adaptations of Princess Lover! and Student Council's Discretion, as well as the anime film Mardock Scramble.

The fictional Ashinaka Academy high school buildings seen in the series are modeled on the Hachioji campus of the Katayanagi Gakuen educational corporation.

The character Neko refers to herself with the archaic pronoun 'wagahai,' a reference to the novel 'I Am a Cat' (Wagahai wa Neko de Aru), which she read as a child.

A special program titled 'K Seisaku Happyoukai WHITE & BLACK' aired on AT-X on October 2, 2012, showing footage from the production announcement event held in August 2012.

A sequel was announced right at the end of the final episode (episode 13) of the first season, later confirmed on May 26, 2013 to be the theatrical film 'K Missing Kings,' released in 2014.

Following the theatrical film, a second TV season titled 'K Return of Kings' was announced in October 2014 and confirmed for an October 2015 broadcast on February 11, 2015.

After the second season ended, a new project titled 'K Seven Stories' was announced on April 30, 2016, alongside the launch of an official fan club called the 'K Official Supporters Clan'; the seven films were released sequentially from July to December 2018.