Shanahan is the writer/director of The New York Times Critics’ Pick “A Sherlock Carol” (Off-Broadway Alliance nomination, Best New Play 2021), playing two seasons in New York and annually at London’s Marylebone Theatre. He recently directed his own adaptation of “Agatha Christie’s The Murder of Roger Ackroyd,” in partnership with Agatha Christie Ltd., premiering this month at the Tony Award-winning Alley Theatre. He is the author of “A Merry Little Christmas Carol,” “See Monsters of the Deep,” the Off-Broadway and regional hit comedy “The Dingdong,” as well as numerous radio plays as creator of the White Heron Ghost Light series, featuring Christopher Plummer, Judith Ivey, Rhonda Ross, and other notables.

Shanahan has directed at stages around the country such as Alley Theatre, George Street Playhouse, Virginia Stage, Arkansas Rep, White Heron, Mile Square Theatre, Hudson Stage, Theatre Squared, Fulton Opera House, Weston Playhouse, Orlando Shakespeare Festival, Florida Rep, Penguin Rep, Merrimack Rep, The Cape Playhouse, and many more.

As an actor, he has appeared on and Off-Broadway (“The 39 Steps,” “Tryst,” “The Shaugraun,” and others) and at many celebrated regional theatres.

Shanahan has appeared on the Westport Country Playhouse stage as an actor in “Journey’s End” (2005) “David Copperfield,” directed by Joanne Woodward and Annie Keefe, (2005), “Sedition” (2007), “Tryst” (2008), and “Around the World in 80 Days” (2009) and numerous Script In Hand readings.

He is also the creator and curator of Westport Country Playhouse Radio Theater, in partnership with WSHU Public Radio, and served as writer/director of the Playhouse radio adaptation of “A Merry Little Christmas Carol,” and as director of scripts commissioned for the series. mark-shanahan.net.