Tomomi Mochizuki is a Japanese storyboard artist, screenwriter, and animation director born on December 31, 1958, in Hokkaido, Japan. He is recognized for his extensive collaborative work with leading animation studios such as Studio Ghibli, Pierrot, and Sunrise and has occasionally used the alias Gō Sakamoto for screenplay and storyboard work. His career began after he developed an interest in animation while attending Waseda University, where he was a member of the university's animation club. In 1981, he started working at the animation studio Ajia-do Animation Works, initially as an animator before making his directorial debut in 1982 on an episode of the series Tokimeki Tonight.

Mochizuki gained early recognition for his work on the magical girl genre, directing episodes of the popular series Magical Angel Creamy Mami, where he developed a reputation for a realistic portrayal of daily life and innovative camera techniques. He served as the chief director for the series Hikari no Densetsu in 1986. He further established his versatility by working on the Ranma ½ series and directing the film Kimagure Orange Road: I Want to Return to That Day. A significant milestone in his career came in 1993 when he directed the television special Ocean Waves for Studio Ghibli, making him the first director outside of founders Hayao Miyazaki and Isao Takahisa to helm a project for the studio.

Regarding his connection to the magical girl anime Fancy Lala, Mochizuki is credited as a writer for the 1998 television series. The show, produced by Studio Pierrot, follows a young girl who gains the ability to transform into a pop star. While the original character designs were created by Akemi Takada, Mochizuki contributed to the series composition and scripts, adding to his long history of involvement in the magical girl and youth drama genres.

As an original creator and director, Mochizuki is known for a distinctive artistic identity that blends meticulous attention to everyday life with expressive direction. His style often involves elaborate layouts, unusual camera angles, and a focus on the subtle emotions and misunderstandings between male and female characters. He has expressed a preference for youth dramas and stories about girls, while also stating a personal discomfort with mecha anime and fantasy stories involving swords and sorcery. His filmography includes directing a wide range of works such as Here Is Greenwood, the Dirty Pair Flash sequels, Seraphim Call, Princess Nine, Twin Spica, and Yokohama Kaidashi Kikō. He also directed the series House of Five Leaves in 2010 and Battery in 2016.

In his personal life, Mochizuki has been married to fellow animator Masako Gotō since 1988. He left Ajia-do Animation Works in 2009 to work as a freelancer. In the 2020s, he publicly disclosed that he had been diagnosed with esophageal cancer and gastrointestinal cancer, stating that he had survived beyond an initial five-year prognosis and continued to work in the industry as his health permitted. His industry significance lies in his versatile directing style that helped push the boundaries of limited animation in television, his success across multiple major studios, and his influence on the realistic portrayal of character drama in anime.