Ronald McDonald was introduced in 1963 as McDonald’s first major television mascot.
The character was created to give the chain a memorable, family-friendly personality on television. The earliest Ronald McDonald was played by Willard Scott, who was then working as a television personality in the Washington, D.C., area. The character’s costume was based around McDonald’s food and restaurant imagery, including a tray-like hat and a striped outfit.
Ronald later became the central figure in the fictional McDonaldland setting, where he appeared alongside characters such as Grimace and Mayor McCheese. His design and portrayal changed over time, but the red-haired clown remained closely associated with the brand for decades.
This question concerns Ronald’s introduction, not the later arrival of other McDonaldland characters. The Hamburglar, for example, is a separate mascot introduced later and is known for stealing hamburgers in the advertising stories.