On April 15, 2019, Thomas joined a host of other writers in firing their agents as part of the WGA's stand against the ATA and the practice of packaging.

[5] In addition to his writing, Thomas has fundraised extensively for Dr. Paul Grossfeld's lab at the Rady Children's Hospital of San Diego.

In 1996, Thomas and Carter Bays (with whom he would later create How I Met Your Mother) formed the power pop band The Solids with fellow Wesleyan University students Patrick Butler and Nick Coleman.

The band went on to write the theme songs for two television shows: Oliver Beene and How I Met Your Mother.

In addition to writing for television, Thomas has been published in the New Yorker's Shouts & Murmurs column five times (Bad Reviews of Beloved Classics, RE: The Asteroid, Studio Notes on Your Rom-Com Screenplay, One Writer's Year in Pandemic Think Pieces, A Look Back at March 12, 2020), McSweeney's, the Boston Globe, and the Iowa Review.