Masanori Morita is a Japanese manga artist born on December 22, 1966, in Rittō, Shiga Prefecture. As a child, he was strongly influenced by the work of Osamu Tezuka and Fujiko Fujio. He is the eldest son of a Jodo Shinshu Buddhist monk, and his family home is a temple of the Honganji sect. While still in high school at age fifteen, he made his debut with the one-shot IT'S LATE, which received an honorable mention at the 27th Tezuka Award and was published in Fresh Jump. After graduating, he moved to Tokyo with the goal of becoming a professional manga artist. He initially sought to become an assistant to Tsukasa Hojo but was turned away; Hojo instead recommended him to Tetsuo Hara, who was looking for assistants. Morita subsequently worked on Hokuto no Ken for about one year.

Morita is best known as the original creator of two major sports and delinquency-themed manga series. His first long-running serialization, Rokudenashi Blues, was published in Shueisha's Weekly Shonen Jump from 1988 to 1997 and collected in 42 tankobon volumes. The story centers on Taison Maeda, a student at Teiken High School in Tokyo who aspires to become a professional boxer while overcoming various rivals. This manga was adapted into a 1992 anime film and the 1993 anime film Rokudenashi Blues 1993. It also inspired live-action films in 1996 and 1998, as well as a live-action television series that debuted in 2011. A stage play adaptation ran in December 2010. In January 2026, it was announced that artist Boichi would draw a new manga for Morita's original work, titled Rokudenashi Blues Gaiden: Onikazura, set to launch in Grand Jump magazine.

Following the conclusion of Rokudenashi Blues, Morita began his next major series, Rookies, which was serialized in Weekly Shonen Jump from February 1998 to August 2003 and collected in 24 tankobon volumes. The story follows an amateur teacher, Koichi Kawato, who takes charge of a high school baseball club composed of delinquent students and helps them pursue their dream of reaching the Koshien baseball tournament. Rookies became one of the best-selling manga series, with over 21 million copies in circulation. It was adapted into a live-action television series broadcast on TBS from April to July 2008, followed by a feature film titled Rookies: Graduation, which premiered in Japanese cinemas on May 31, 2009.

Morita continued creating manga with Beshari-Gurashi, serialized from 2005 to 2015 with an additional chapter in 2019. The series began in Weekly Shonen Jump before moving to Weekly Young Jump at the author's request due to health issues that made a weekly schedule difficult to maintain. This series was nominated for the 17th Osamu Tezuka Cultural Prize. In 2022, he began serializing Zashisu, a thriller with a tone different from his previous works, in Shueisha's Grand Jump magazine.

Recurring themes in Morita's work include youth, perseverance, and personal growth, often framed within the context of school life and sports. Both Rokudenashi Blues and Rookies prominently feature delinquent protagonists who find purpose and redemption through athletics and mentorship. His artistic style is characterized by detailed pen lines and a focus on facial expressions, with a distinctive method of drawing faces by first rendering the eyes, nose, and mouth before outlining the head and body. He is a known fan of the Hanshin Tigers baseball team, and his works frequently reference the team. Several artists who once worked as his assistants have gone on to become successful manga creators, including Daimurō Kishi, Nobuhisa Tsuruoka, Yasuteru Iwata, and Makoto Itō.

Masanori Morita holds significant industry standing as a pioneering figure in the school delinquency genre, with Rokudenashi Blues considered a foundational work that influenced many subsequent series. His commercial success with both Rokudenashi Blues and Rookies, as well as their numerous live-action adaptations, has cemented his legacy as a major creator in Shueisha's publications.