Theodor has been writing stories since he was young but it took until 2020 to see his work in print, with his story Remembrances winning Second Prize in the Quarterly 1000 Word Competition and his poem The Man from Kathmandu shortlisted for the Percy French Prize for Witty Verse at Strokestown's 2020 International Poetry Festival. His short piece The Last House in London was also the unanimous winner of Litopia's Live Pop-Up Submissions that same year.

In April 2020 Theodor published his first novel, The Winter Wilds; a story about a young Englishman far from home who — despite his own best efforts — is swept up in a series of strange events. Also featured are a vicious corporate power struggle, lots of mountain-related trivia, some mild supernatural peril, and a goat named Jerome.

In non-fiction, Theodor's penned over two hundred ads for the American radio market as a freelance marketing copywriter and contributed a number of essays, reviews and commentary to student journalism during his studies.