Guillermo is a writer of drama and fiction as well as a director, dramaturge, translator, and actor. He is the recipient of a Governor-General’s Award for Drama for his play Fronteras Americanas and a four-time winner of the Chalmers Canadian Play Award. His work, which includes Feast, the Governor-General’s Award shortlisted Noam Chomsky Lectures (with Daniel Brooks), the Seattle Times’ Footlight Award-winning Adventures of Ali & Ali (with Marcus Youssef and Camyar Chai), A Line in the Sand (with Marcus Youssef), Our Heart Learns, bloom, and Another Country has been recorded, anthologized, translated into Spanish and Italian, produced in Europe, Australia, and the US, and is studied in Latin America, Australia, Europe, and North America.

A director and actor, he has worked at theatres across Canada, and has also translated plays by Federico Garcia Lorca and Ximena Escalante.

His newest work, Versus (co-created with Adam Lazarus and Ann-Marie Kerr) will premiere in Toronto in early 2026.