Aoyama was talented in drawing even at an early age. When he was in Grade 1 in elementary school, his painting of "Yukiai War" won a competition and was displayed at the Tottori Daimaru Department Store.

He graduated from high school at Yuraikuei High School. He then went on to study in Nihon University College of Art in Tokyo. In winter of 1986, Aoyama joined a comic contest for freshmen students. He won the contest, and it became a stepping-stone for his career as a manga artist and author, as well as a turning point for his life.

Aoyama made his debut as a manga artist with the work Chotto Matte which was published in the weekly magazine Sh?nen Sunday on winter of 1987. Shortly after that, another work by Aoyama, Magic Kaito, was published on the same magazine.

In the early 1990s, another story done by Aoyama named Yaiba came out; the manga series was released in 24 volumes. Later, he would release other manga series in volumes (tank?bon), such as Third Baseman No.4, Gosho Aoyama's Collection of Short Stories, and Detective Conan.

Aoyama has won two awards for his work as a manga artist. In 1992, he won the Shogakukan Manga Award for sh?nen for the Yaiba manga series. He would then go on to win the same award for a second time in 2001, this time for Detective Conan.

Additionally, his hometown Hokuei has done several machi okoshi (town revitalization) projects in honor of his contribution as a manga artist and resident of the town. The first projects were the Conan Bridge across the Yura River and the Conan statues in the town; both of these structures pay tribute to Conan Edogawa, Aoyama's most popular character from Detective Conan. On March 18, 2007, the Gosho Aoyama Manga Factory, a museum that celebrates Aoyama's career as a manga artist, was opened in the same town.

On May 5, 2005, he was married to Minami Takayama, a singer and voice actress who gave the voice of Conan in the original Japanese anime adaptation of Aoyama's Detective Conan. In December 10, 2007, the two were divorced.