Walter was a man living in Mercy, Nevada, in 1870.
Upon learning the Eleventh Doctor was an alien doctor, he and several men were quick to throw him out of town to save themselves from the Gunslinger's wrath. Nevertheless, he trusted Isaac's judgement and followed his example in letting the Doctor back in.
Upon the Doctor's departure, Walter tipped his hat to him in a gesture of thanks for all he had done. (TV: A Town Called Mercy)
