On December 22, 1989, a Famicom cartridge called Akumajō Densetsu went on sale in Japan. Inside it was an extra sound chip, Konami's VRC6, which gave the console two more square-wave channels and one sawtooth channel on top of the five it already had. The music staff listed for the game on the Video Game Music Preservation Foundation wiki includes Jun Funahashi. Less than a year later the game reached North America as Castlevania III: Dracula's Curse, without that chip. The soundtrack was reworked to fit the console's built-in channels.
Funahashi had started composing for Konami in the mid-1980s. The earliest credit the wiki lists for him is Nazo no Kabe: Block Kuzushi, released on December 13, 1986, for the Famicom Disk System. He is known by several aliases, including Dog-Man. The wiki lists no job title next to most of his early games, so what exactly he wrote on each one is not something we can say.
One part of his work is described more clearly: he helped Konami improve its NES sound driver. A sound driver is the small program that reads a composer's music data and turns it into instructions for the sound chip. Every note in a game passes through it. According to the wiki, earlier Konami games used a driver by Hidenori Maezawa or one by Atsushi Fujio, depending on who supervised the sound. Funahashi later worked with Tsutomu Ogura on a custom version of his own. Players never see this layer. A bad one is the kind of thing they would hear.
The credits then run through the 1990s: The Adventures of Bayou Billy in 1988, Teenage Mutant Ninja Turtles in 1989, Tiny Toon Adventures in 1991, Batman Returns on the Super Nintendo in 1993, where the wiki says he worked with various members of the Konami Kukeiha Club. For Lethal Enforcers on the Super Famicom in 1994, he is listed for sound effects. Many other lines have no role written beside them at all.
After 1999 the listed roles change. For Frogger's Adventures: Temple of the Frog on the Game Boy Advance in 2001, he is listed as Audio Manager and Director. The same kind of title follows for Frogger Beyond on the GameCube in 2002, Dance Dance Revolution Ultramix 2 on the Xbox in 2004, and Ys VI: The Ark of Napishtim on the PlayStation 2 in 2005. The wiki also says he became music director at Konami Computer Entertainment Hawaii around 2000. We could find that statement in only one place, and the developer credits we checked for the Frogger games disagree with each other, so we cannot confirm it independently.
What the record does show is that he did not leave. His listed work continues for years after the date some accounts give as the end of his career. The last credit on the wiki page is Stranglehold on the PlayStation 3 in 2007, where he is listed for additional audio support. The work changed from writing the notes to making sure a team's sound got finished and shipped.
We found no dated interview in which he explains his own work in his own words, so this story does not put any in his mouth. There are only the credits, the driver, and the order in which they appear: first the notes, then the tool the notes passed through, then the people who made the notes.
A driver is judged by whether anyone notices it, and a manager's credit is judged by whether the game ships with its sound intact. The best result of that kind of work is that nobody thinks about it. If the part of your work you do best is the part no one will ever think to credit, would you still make it that well?