Although born in Shizuoka, Usui grew up in Kasukabe, Saitama, the same city Crayon Shin-chan took place in and he cited he was inspired by his own childhood while creating the series. The city has been a very popular tourism destination for fans of the series.

While working in an advertising agency in the 80s, and making ads for supermarkets, he was sending manga to any editor he may know. He made his debut in 1987.

In 2004, he visited Barcelona, in Spain, to promote Crayon Shin-chan there, and was moved and touched for the reception his work had there. He got inspired by his visit that he eventually wrote a chapter of the cast visiting the city. He even became friends with the then-Spanish translator of the series, Marc Bernabé, whom has made very small cameos in the anime series.

On September 12th, 2009, Usui's family reported him as missing, since he didn't return from hiking (one of his favorite hobbies). A week later, a body whose clothes resembled his was found at Arafune mountain. And on Sunday, September 20, 2009, authorities identified the body discovered as that of Usui, through dental records and other means. He was 51 years old.

The Crayon Shin-chan article in the English Wikipedia adds:

"Due to the death of author Usui, the manga in its current form ended on September 11, 2009, as announced in a broadcast of the anime on October 16, 2009. Although the series formally ended on February 5, 2010, it was announced on December 1, 2009 that a new manga would begin in the summer of 2010 by members of Usui's team."