He is one of Mickey's friends and the boyfriend of Clarabelle Cow. Horace first appeared as Mickey's plow horse in The Plow Boy in 1929. Since then he appeared as an anthropomorphized horse with the personality of a cheerful know-it-all. Horace helped Mickey on his sleuthing expeditions in the comics before Goofy was created; in recent years, Horace has more commonly appeared in day-to-day gag situations.
Horace has never really been more than a supporting character, though he has starred in numerous European comic book stories of his own. On modern television, he appeared in a few segments of Mickey Mouse Works. He also appears in House of Mouse as the club's mechanical technician.