Ronald McDonald appeared in McDonald's 1963 television advertising in a version played by Willard Scott.
Scott portrayed the character in early Washington, D.C.-area commercials, helping establish the red-haired clown as a recognizable McDonald's figure. The character's costume and appearance changed over time as the company developed a more standardized national identity.
Ronald McDonald later became the central human-like mascot within McDonaldland and appeared in advertising, restaurant promotions, and charity-related branding. His role was broader than promoting one specific menu item.
Willard Scott's early portrayal is sometimes confused with the later, standardized Ronald used nationally. The question concerns the early television appearance, not every actor who subsequently played the character.