Aoyama was a genius at drawing even when young. 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 Ikuei High School. After finishing high school, he studied to Nihon University College of Art in Tokyo. During his university years (winter 1986), Aoyama joined a comic contest for freshmen and won, which was a stepping-stone for his career as a manga artist (mangaka) and author, as well as a turning point for his life.

Aoyama's debut work was Chotto Mattete, published in the weekly magazine Shonen Sunday on winter 1987. Shortly after that, Magic Kaito was published on the same magazine.

At the beginning of the 90's, another story done by Aoyama named Yaiba was out. This 24-volume manga won the Shogakukan Manga Award for shōnen in 1993. He won the Shogakukan Manga Award a second time in 2001, for Detective Conan. Other works were released as tankōbon included Third Baseman No.4, Gosho Aoyama's Collection of Short Stories, and Detective Conan.

On May 5, 2005, he married voice actress and singer Minami Takayama, the Japanese voice for Conan of the Detective Conan anime, but they divorced on December 10, 2007.