U-Jin, whose real name is not publicly disclosed, is a Japanese manga artist born on June 15, 1959, in Ube, Yamaguchi Prefecture. He began his professional career in 1979 with the manga Dousei Keiyaku and initially published his work in seinen magazines such as Weekly Morning. His artistic pseudonym, written as 遊人 (Yūjin), translates to meaning "the man who enjoys himself," a name that reflects the playful and often adult-oriented nature of his work.

U-Jin rose to prominence with the serialization of Angel in Shogakukan’s Weekly Young Sunday magazine in 1988. This series, a comedic story involving a high school boy and a girl with superhuman strength, became a landmark work in his career and established his reputation within the erotic comedy genre. The series was notably controversial; the cover art of its collected edition was criticized for being indistinguishable from children’s books, which contributed to a broader movement towards the censorship of sexually explicit content in mainstream Japanese publications. Following its cancellation, the series was later re-published by a publisher specializing in adult content.

Over his career, U-Jin has been credited as the original creator for numerous manga that have been adapted into original video animations. These adaptations include Angel, Fobia, Juliet, Kyūkyoku no Chef wa Oishinbo Papa, and Mail Order Maiden 28, among others. His manga series Sakura Diaries, which ran from 1995 to 2000, stands as another major work in his bibliography and was also adapted into an OVA series and a video game. Many of his other works, such as Kōnai Shasei (School Sketch), Private Psycho Lesson, and Vixens, similarly received OVA adaptations.

U-Jin’s artistic identity is strongly associated with the erotic and ecchi genres, with his work frequently featuring what has been described as "cute pneumatic female figures". Beyond his narrative work, he has also published several art books, including U-Jeune, Loose Socks, and Candy. He is known to have a personal interest in playing the piano, a hobby that has occasionally been reflected in the characters he creates.