Ehn is a playwright, educator and theorist of contemporary theater. He recently collaborated with Janie Geiser on Invisible Glass inspired by Edgar Allan Poe's short story, "William Wilson." It premiered at the Roy and Edna Disney/CalArts Theater (REDCAT) in April 2005.
His play Maria Kizito is based on the 1994 genocide in Rwanda and is the result of his research in that Central African country. Its premiere launched Atlanta's 7 Stages 2004-05 season. Ehn's work includes The Saint Plays, an ongoing cycle of plays loosely based on the lives of the saints and biblical characters. Other plays include Book of Tink, Heavenly Shades of Night are Falling, No Time Like the Present, Wolf at the Door, Tailings, Beginner, Ideas of Good and Evil, 13 Christs and an adaptation of William Faulkner's The Sound and the Fury. Additionally, he co-wrote the musical Shiner with Octavio Solis. His dramas have been produced in San Francisco, Seattle, Austin, Dallas, New York City, San Diego, Baltimore, and Chicago. In 2004, he served as dramaturge on Peach Blossom Fan - the inaugural production by CalArts Center for New Theater at REDCAT.
Ehn is co-founder and co-artistic director, alongside Lisa Bielawa, of the Tenderloin Opera Company in San Francisco and also an artistic associate of San Francisco's Theatre of Yugen. He is a co-founder of the RAT movement, an international network of alternative theaters. He was a recipient of the Alpert Award in the Arts in 2002 and the Whiting Writers Award in 1997.