Kazuya Tsurumaki was born on February 2, 1966, in Gosen, Niigata Prefecture, Japan. He is a Japanese animator, anime director, and original creator, best known as a long-time protégé of director Hideaki Anno. Tsurumaki began his career at the animation studio Gainax, where his first project was as an animation director for the 1990 television series Nadia: The Secret of Blue Water. He later served as assistant director under Anno on the landmark series Neon Genesis Evangelion (1995), handling production duties, storyboards, and direction for several episodes. In 1997, he directed episode 25, the first half of the cinematic conclusion The End of Evangelion.

Tsurumaki made his full directorial debut with the original six-part OVA series FLCL in 2000, a project he also conceived. He went on to direct the 2004 sequel series Gunbuster 2, also known as Diebuster. Following his time at Gainax, he joined Hideaki Anno at the newly founded Studio Khara, where he served as a co-director on the four-film Rebuild of Evangelion series.

As an original creator, Tsurumaki is credited with the concept for the anime and manga franchise Getsumen to Heiki Mina. This project originally began as a fictitious anime within the television miniseries Densha Otoko before being adapted into a real television series. The anime was produced by Gonzo and aired for eleven episodes in 2007. Tsurumaki is listed as the original creator of the series, which follows a group of rabbit-themed transforming heroines known as Rabbit Force who enforce an intergalactic treaty protecting Earth's sports culture from alien fans. A two-volume manga adaptation of Getsumen to Heiki Mina was later published by MediaWorks, written by Nylon with illustration by okama and Takashi Kumazen, though some sources list Tsurumaki as the author of the manga as well.

Tsurumaki's artistic identity is characterized by a focus on the psychological growth of young protagonists, often featuring anxious or insecure male leads navigating chaotic, coming-of-age stories. His works are noted for dense, systematic worldbuilding, frenetic pacing, and a blend of surrealist physical comedy with deconstructionist storytelling techniques. He has cited a personal interest in depicting weak, insecure characters, and has stated that the absence of parents in many Gainax series reflects the workaholic nature of Japanese family life, including his own experiences. Tsurumaki is considered a significant figure in the Japanese animation industry, having mentored numerous second-generation directors from Gainax, including Atsushi Nishigori, Hiroyuki Imaishi, and Shingo Natsume. He remains an active director, having been announced as the series director for the upcoming Gundam series Mobile Suit Gundam GQuuuuuuX.