As of 2011[update], Matsumoto is the Chief Architect of Ruby at Heroku, an online cloud platform-as-a-service in San Francisco.

[2] He graduated with an information science degree from University of Tsukuba where he was a member of Ikuo Nakata's research lab on programming languages and compilers.

He has released several open source products, including cmail, the Emacs-based mail user agent, written entirely in Emacs Lisp.

[6][7] It is a minimal implementation based on his virtual machine, ritevm, and is designed to allow software developers to embed Ruby in other programs while keeping memory footprint small and performance optimized.

[8] Matsumoto has been listed as an investor for Treasure Data; many of the company's programs such as Fluentd use Ruby as their primary language.