He is best known for the creation of the A Certain Magical Index franchise which, as of 2019, has sold over 30 million copies worldwide and has been licensed in North America by Yen Press with the first novel being released in Q4 2014.

[1][2] Kazuma Kamachi has stated that ever since he was a child, he had always wanted to become a novelist, spending his student days in trying to achieve this dream.

[4] For around a year, Kamachi exchanged and discussed prototype stories with Miki,[4][5] and made his debut with A Certain Magical Index in April 2004 after 6 or 7 revisions.

In April 2016, Kamachi signed a contract to write for Kazuma Miki's new company Straight Edge Inc. On July 10, 2020, he became the first Dengeki writer to have published 100 volumes under their label.

[5] Not much is known about Kazuma Kamachi's personal life, which is also true for other light novel authors in Japan.