
In 2006, he was chosen, along with Akira Toriyama and Eiichiro Oda, to be a committee member for the Tezuka Award. The company name, which translates to "rice", was chosen for three reasons: 1) because "Inagaki" contains a kanji ("稲") that can be translated to rice 2) because "rice" kanji ("米") is also used to represent the United States and 3) because of the Rice Bowl, an American football championship in Japan.

For the release of Eyeshield 21 anime he created the Kome Studio, a company of copyright management to ensure the right of the original creators of manga. It has sold more than 20 million copies in Japan, has been published in seven countries, including in the United States, and gained an anime adaptation that aired for 145 episodes from April 2005 to March 2008 on TV Tokyo. Collected in 37 volumes by Shueisha, the series became his most known work. The series began to be regularly published on July 23 of the same year in the same magazine, and spanned 333 chapters, the last one being published on June 15, 2009. In 2002, they published two one-shots called Eyeshield Part 1 ( 前編, Zenpen) and Part 2 ( 後編, Kōhen) on March 5 and 12 in Weekly Shōnen Jump. So he asked Yusuke Murata to be the illustrator.

When he planned to create Eyeshield 21, the editorial department asked if he wanted to both write and draw the series, but Inagaki felt he was "so rookie". He later moved to Shueisha's Weekly Shōnen Jump, in which he won the 7th "Story King" award for a storyboard of Eyeshield 21.

He debuted in October 2001 with Nandodemo Roku Gatsu Jū San Hi, and also wrote for the magazine Square Freeze and Love Love Santa, published in November 2001 and in February 2002 respectively. He started his career as professional manga writer by publishing works in Shogakukan's Big Comic Spirits. After finishing school, he enrolled in a manga and film production company as animation assistant. But Manga Koshien isn't something I'm so fond of remembering". He said, "People really liked that for some reason. As it only demanded a one-panel story, Inagaki just threw some ink on the paper to look like he had messed up the story. In 1994, he competed at the third Manga Kōshien, a high school manga contest based in Kōchi Prefecture.

Born on June 20, 1976, in Tokyo, Inagaki started to like manga when he read Fujiko Fujio's Manga Michi in middle school.
