Seamus McFly was the husband to Maggie McFly. He was Irish by birth and together with his brother Martin moved to the United States from Ireland in the 1880s. Seamus appeared to be in his mid-twenties to early-thirties in 1885, and his religion was the Roman Catholic faith. Seamus also liked unusual hats, one of which he gave to "Clint Eastwood" who was, in reality, his future great-great-grandson Marty McFly. Seamus's name would be given to Marty as a middle name, presumably by George.