Speedee was McDonald's first national advertising mascot before Ronald McDonald became dominant.
The mascot was created to symbolize the McDonald brothers' Speedee Service System, introduced when the restaurant emphasized quick, standardized food preparation. Speedee's chef-like appearance and hamburger head made the connection between speed, cooking, and hamburgers visually clear.
As McDonald's expanded and sought a stronger family-oriented identity, Ronald McDonald and the McDonaldland characters became more prominent. Speedee consequently disappeared from most mainstream consumer branding, although he remains important in historical accounts of the company's early identity.
This question is often confused by the fact that Speedee and Ronald served different branding purposes. Speedee represented operational efficiency, while Ronald was built as a character who could lead children's advertising and appear in an imaginative story world.