Lassie was a Rough Collie. This breed is known for its long, beautiful coat, intelligence, energy, and herding and protecting abilities. The Rough Collie is a medium to large-sized dog originally bred in Scotland to herd sheep. Lassie, though a fictional character, was portrayed by Rough Collies in films and TV shows, starting with a Rough Collie named Pal in the 1943 movie "Lassie Come Home".