The story focuses on side characters from the animated television series Pretty Rhythm: Rainbow Live, which aired from 2013 to 2014.

[4] After Louis Kisaragi gives him a locket and instructs him to attend Over the Rainbow's Prism Show, Shin Ichijo is starstruck from the experience.

While Shin bikes home, Hijiri Himuro, noticing his sparkle, sees potential in him and scouts him to become a Prism Star trainee at Edel Rose Academy.

The post-credits scene features a preview for a proposed continuation, where in the midst of preparations for the next Prism King Cup tournament, Hiro learns that he is unable to perform "Pride" now that the song has been given to Louis.

Pretty Rhythm director Masakazu Hishida had stressed the importance of the male characters of Pretty Rhythm: Rainbow Live, and with them debuting as Over the Rainbow in the final episode, Hiroko Nishi and Takeshi Yoda had wanted to develop a late-night 13-episode television series that would focus on them, but their original plan was rejected.

[5] From 2014 onward, the staff continued to promote various Pretty Rhythm and PriPara series at events, occasionally teasing Over the Rainbow's comeback to test the fans' feedback.

Over the Rainbow's comeback was later confirmed at an Edel Rose event in 2015, where a VTR clip show announced that they would return in a film project in 2016 titled King of Prism by Pretty Rhythm.

[4] During a live stream on December 22, 2015, Hishida addressed criticisms about the Pretty Rhythm series and revealed that the film project was given limited time and budget, leading the staff had debated how much of the story they could fit in 60 minutes.

[20] Initial box office revenue for King of Prism by Pretty Rhythm was poor, and there were considerations of ending the screenings after its second week.

[24] King of Prism by Pretty Rhythm also spearheaded the "cheer screenings" movement and popularized it in modern cinema,[25] with multiple fans who attending them several times.

[15] After the success of the film, a theatrical sequel titled King of Prism: Pride the Hero was announced in 2016[30] and released in theaters on June 10, 2017.

[36] The cast consists of Shohei Hashimoto as Shin, Koji Kominami as Koji, Taishi Sugie as Hiro, Takuto Omi as Kazuki, Shojiro Yokoi as Yukinojo, Ryoki Nagae as Taiga, Yoshiki Murakami as Kakeru, Yuzuki Hoshimoto as Leo, Ryota Hirono as Yu, Taiki Naito as Louis, Spi as Alexander, and Yamato Furuya as Joji.

[37][38] A manga adaptation titled King of Prism by Pretty Rhythm Party Time was drawn by Sumika Sumio and serialized in Monthly GFantasy.