Born to a Scottish mother and Irish father, David Coyle (Brendan is his stage name) lived in Dublin and London during his youth. With no thought of an acting career, Coyle worked in his dad's butcher shop after leaving school. It wasn't until his father died that he sought a change. Inspired by a Shakespeare production that he'd seen in school, Coyle contacted an Irish aunt who he knew ran a theater company and was soon enrolled in drama school in Dublin. Now a veteran of the British stage, Coyle has appeared in many television dramas including North and South, Lark Rise to Candleford, and on MASTERPIECE in Prime Suspect 7: The Final Act and Jericho. Most recently, Coyle starred in the British television drama series Starlings.

Downton Abbey creator Julian Fellowes knew Coyle would be perfect for the part. "I wrote John Bates for Brendan. I knew he had the capacity to suggest a character's bitter and painful past without doing much to indicate it," Fellowes said. "Above all, he never asks for sympathy as an actor, and consequently he gets it."

In Season 3, however, Coyle's character deserves more sympathy than ever. Coyle describes his experience filming, saying, "Victorian prisons were really grim. There are no windows, no heating, it's just stone walls. It would have been really cold, a harsh climate, poor diet and a punishing regime as well. I read up about stuff like that – it was a very, very miserable existence. There was a high suicide rate too, unsurprisingly. A lot of hanging."