Jang Min-gyu begin first youth career with Bupyeong High School, when entered to Hanyang University.
In 2019, he was selected for the first time to the South Korea national under-23 football team, which is aiming to qualify for the 2020 Olympics in Tokyo.
18 December 2019, Jang Min-gyu was abroad to Japan for the first time and begin first professional career with JEF United Chiba from 2020 season.
[2] On 8 January 2025, Machida announce that would be leaving the team to complete procedures and preparations for transferring to an overseas club.
[3] Eight days later in same year, Jang Min-gyu announcement officially return to South Korea and transfer to K League 1 club, Jeju SK for 2025 season.