His research and teaching interests include: digital humanities, digital scholarly editions, textual scholarship, documentation, and bibliography; poetry and poetics; comic books and graphic novels; history of the book; and digital libraries. He is Editor of The Algernon Charles Swinburne Project, Technical Editor of the Chymistry of Isaac Newton, and Co-Editor with H. Wayne Storey of the Petrarchive. Walsh is the lead developer of Comic Book Markup Language and TEI Boilerplate. He is a member of the Steering Committee and Victorian Editorial Board of NINES, Editor of the Journal of the Text Encoding Initiative, Technical Editor of Digital Humanities Quarterly, and a member of the Editorial Board of Textual Cultures, the journal of the Society for Textual Scholarship.