He was attending Hita Rinko Senior High School when he began submitting manga works to contests.

In 2006, he applied for the Magazine Grand Prix known as MGP promoted by Kodansha Ltd. and a short version of Attack on Titan (Shingeki no Kyojin) was given the "Fine Work" award.

[8] At age twenty, he moved to Tokyo and worked at an Internet café in order to pursue a career in writing manga.

The resort Bungo Oyama Hibiki no Sato in his hometown of Ōyama, ran a free exhibit displaying copies of Isayama's manuscripts for the manga in 2013.

[9] A special Attack on Titan event was held in Hita on November 1, 2014, with Isayama and approximately 2,500 spectators attending.