Junichi Masuda was born in Yokohama, Japan. Details about his early childhood are scarce, but his later career suggests an early interest in music and technology.

Masuda has expressed having a keen interest in music from a young age. He is known for his abilities as a trombonist, implying musical training from his youth. It is unknown if he played or was involved with music with any ensembles or groups.

Masuda graduated from Japan Electronics College, where he studied programming. This education provided him with the technical skills necessary to enter the video game industry and pursue his interests in game development.