Keigo Misaki is a Japanese science fiction writer and original creator, primarily known for his work in the late twentieth century. He was born on December 30, 1954, in Tokyo, Japan. He graduated from the Faculty of Law at Kokugakuin University. His professional writing career began in 1979 when his short story "Tōjō no Kyōi" (Threat Overhead) was published in the March issue of SF Magazine.

Misaki adopted his pen name from the short story "Misaki nite" by the renowned Japanese author Komatsu Sakyō, a work that had a profound impact on him. He was a regular contributor to the "Readers' Story" section of SF Magazine, which was run by the author Aran Toyota, and he later joined Toyota's creative group, Parallel Creation.

In his early work, Misaki focused on writing what is often described as "idea SF." However, he gained wider recognition and popularity among younger readers for his Love Pair series, a collection of comedic science fiction stories that resonated with a contemporary sensibility. The series began in 1985 with the novel Majo de mo Steady, which translates to "My Steady Is a Witch." This novel is his most directly relevant work in the context of anime and manga, as it was adapted into an original video animation (OVA) in 1986. The OVA, which shares the same title, is a single-episode production that blends comedy, science fiction, and magical elements. The story involves an ordinary man who wakes up to find a mysterious girl from a parallel dimension in his room, leading to a series of strange events.

The adaptation of Majo de mo Steady is a key example of the pipeline from light novel to anime in the mid-1980s. The OVA was produced by the studio Tokyo Media Connections, with direction by Osamu Kobayashi and a screenplay by Reiko Nakata. The character designs for both the original novel and the OVA were handled by the manga artist and writer Miki Tori.

Beyond the Love Pair series, which includes other titles such as Megami ni Goodbye, Daimaō ni Attack, and Chitei Dodonpa Otoko, Misaki also authored the Dimension Agent Sadistic Mariya series. In the mid-1990s, during a period known as the "winter era" for science fiction in Japan, Misaki collaborated with his wife, who is also a prominent SF writer, to edit and publish the original anthology series SF Baka Hon. This series ran until 2007, and Misaki was also responsible for the cover CG art for the 2000 edition.

Misaki is married to the SF writer Mariko Ohara. During the time he was writing Majo de mo Steady, he, his wife, and Miki Tori were part of a band called the Flat Hips. According to his wife's blog, as of 2021, Keigo Misaki has been battling Guillain-Barré syndrome, a rare neurological disorder.