[1] His work as a programmer includes creating GNU Image Manipulation Program (GIMP) while still in college,[2] and assisting the source code development of CockroachDB, the namesake software of Cockroach Labs.

While still a student in 1995, he developed the first version of GNU Image Manipulation Program (GIMP) as a class project, along with his roommate Peter Mattis.

After using emacs, gcc, Linux, etc., I really felt that I owed a debt to the community which had, to a large degree, shaped my computing development.

[8] While at XCF, he met Gene Kan, who was also a member, and the two would later begin working together on a file-sharing program for the Gnutella network, the open source Unix/Linux client gnubile.

[16] Kimball moved to Square's New York City office where he became a senior member of the company's East Coast team.

[18] They formed the company Cockroach Labs to provide commercial backing for CockroachDB, an open source project he started on GitHub in February 2014.