He was born in Fukuoka Prefecture.
Best known for his writing collaborations with directors Kōji Wakamatsu and Nagisa Oshima, often under the pseudonyms "Izuru Deguchi" or "De Deguchi" (出口出), he also directed a number of his own films, usually dealing with left-wing political themes. He stopped making films in the early 1970s and joined the Japanese Red Army, an armed militant organization. After residing in Lebanon for 28 years, he was arrested for passport violations. He was found guilty of passport violations in September 2001 and received a four-year sentence, suspended to 18 months. After his release he was deported to Japan via Jordan, where he was re-arrested on other passport violations. After being held for a year and a half he was convicted and released based on the time he had already served. Since his release, he has resumed making films after a 30-year absence.
Masao Adachi and Go Hirasawa, Film / Revolution, 2003, 河出書房新社 (in Japanese).
Masao Adachi, Le Bus de la révolution passera bientôt près de chez toi. Ecrits sur le cinéma, la guérilla et l'avant-garde, Rouge Profond éditeur, 2012 (in French)
Eric Baudelaire, "The Anabasis of May and Fusako Shigenobu, Masao Adachi, and 27 years withour images", installation for the MACBA in Barcelona,2011, text in English and Catalan, film 66 min (in English) and 9 screenprints.
- "Masao Adachi". Allmovie. Retrieved 2007-11-17.
- "MASAO ADACHI". The Complete Index to World Film. Retrieved 2007-11-17.
- Masao Adachi (I) at the Internet Movie Database
- 足立正生 (Adachi Masao) at the Japanese Movie Database (Japanese)
- "Claudia Siefen im Gespräch mit Masao Adachi" (in German). dasmanifest.com. May 2007. Retrieved 2008-04-16.
- "Intervista ad Adachi Masao" (in Italian). . May 2007. Retrieved 2008-04-16.
- "Masao Adachi First Complete Retrospective, Cinémathèque française 2010" (in French). .