By high school, Mitsuda wanted to become a music composer, inspired by Vangelis' Blade Runner and Henry Mancini's The Pink Panther film scores.

At the cost of being used for free physical labor, Mitsuda got a first-hand view of the Japanese music world and valuable training both in and out of the classroom.

As part of his college course, he was granted an intern position at the game development studio Wolf Team studying under composer Motoi Sakuraba.

Over the next two years, he created sound effects for Hanjuku Hero, Final Fantasy V, Secret of Mana, and Romancing SaGa 2.

[5] In 1994, realizing that he would never get a chance to move up to a real composition duty without some drastic action and feeling concerned about his low pay, he gave Square's vice president, Hironobu Sakaguchi, an ultimatum: let him compose, or he would quit.

Sakaguchi assigned the young musician to the team working on Chrono Trigger, telling him that "after you finish it, maybe your salary will go up".

1 and Radical Dreamers: Nusumenai Hōseki both in 1996, and Xenogears in 1998, which featured the first ballad in a Square game, the Celtic ending theme "Small Two of Pieces" sung by Joanne Hogg.

In addition to video games, Mitsuda has composed music for the anime Inazuma Eleven and for the independent album Kirite.

[10] On November 22, 2001, Mitsuda formed Procyon Studio as a company to produce his music, along with a record label, Sleigh Bells.

[8] Scores in the 2010s include the Inazuma Eleven series, Soul Sacrifice, and Valkyria Revolution, with the latter marking his first fully solo game soundtrack in nearly a decade.

[10][13][14][15][16] Around the same time, Mitsuda also began to compose for non-video game media, including several NHK-produced television shows, as well as anime series such as Black Butler and adaptions of Inazuma Eleven.

[10][17][18][19] In addition to serving as the lead composer for 2017's Xenoblade Chronicles 2, he also was in charge of the game's audio budget, musician booking, schedule management, and music sheet proofreading, for which he claimed was the largest project he ever worked on.

[23] He also sometimes comes up with songs while asleep, including the ending theme to Chrono Trigger and "Bonds of Sea and Fire" from Xenogears, though his main inspiration is visual items, "paintings or other things".

[5] His soundtrack for Chrono Trigger also shows the influence of Asian music, including the sounds of Japanese shakuhachi flutes, Indian tabla drums and the sitar.

Bach, Pyotr Tchaikovsky, Claude Debussy, Robert Schumann, Antonín Dvořák, and Gustav Holst as his favorite classical composers, claiming that his modern influences are too numerous to name as he listens to so much music.

In that sense, this not only applies to game music, but I feel very strongly about composing songs that will leave a lasting impression...What I must not forget is that it must be entertaining to those who are listening.

[33] The album features 20 tracks arranged from the Xenogears score and performed with acoustic instruments, such as piano, flute, guitar and violin.