Mr. Harold Hooper was one of the first four human characters to appear on the television series Sesame Street. Created by producer and writer Jon Stone, Mr. Hooper is the original proprietor of Hooper's Store, the neighborhood variety store and combination diner/corner store that serves as a place for Muppets and humans to meet and interact. Lee, a character actor and instructor was "perfectly cast" as Mr. Hooper. Mr. Hooper ranked first of all human characters of the show in recognition by young viewers. Mr. Hooper, who has been described as "slightly cranky but good-hearted" and "curmudgeonly", bridges the gap between the older generation and its young audience. Hooper's Store, "an idealized social institution", is an extension of his personality. He had a close relationship with the Muppet Big Bird.

William Lee was an American actor who appeared in numerous television and film roles, but was best known for playing Mr. Hooper, the original store proprietor of the eponymous Hooper's Store. He was one of the four original human characters on Sesame Street, from the show's debut in November 1969 until his death on December 7, 1982, at the age of 74.