While every cock in the kitchen wears a different hat that signifies his or her job (mincing, stirring, etc), it is only the chef that wears a true chef hat, professionally known as a toque.
Long ago, the toque pleats represent the number of recipes the chef had mastered – 50 recipes, 50 pleats; 100 recipes, 100 pleats, and so on and so forth. Though this ranking system is not practiced anymore to the T, it is still accustomed for a more experienced chef to wear a hat with more pleats, even if it’s just three or four.
PS. the same goes for the hat’s height. Once it officially represented the chefs standing. Today it sometimes still plays a role, but not in a mandatory way.
Bonus fact 1: While hats in the kitchen are undoubtedly there to ensure hair does not fall in the dish, their design entails an interesting story.
When the Byzantine Empire invaded Greece (146BC) Greek chefs fled to monasteries for protection. To blend in they wore monks’ outfits that in those days included a large high hat. After the Byzantines were driven back, the chefs continued to wear high hats as a sign of solidarity and a sense of fraternity.
Bonus fact 2: Toque comes from Arabic and in that language, it means a hat, any hat.