King Dedede (King DeDeDe in some older games; sometimes shortened to Dedede) is a portly, blue, penguin-like creature who wields a hammer and proclaims himself as king of Dream Land. He is a recurring character who serves as Kirby's "arch frenemy" and is usually fought as a boss. He has a gluttonous streak, and he often engages in trouble-making, such as stealing all of Dream Land's food and the Sparkling Stars or shooting Mr. Star with a cannon. However, over time he began to perform more noble deeds, such as trying to seal away Nightmare, helping Kirby battle Queen Sectonia, and accompanying Kirby in several of his adventures. Because of this, he is considered a protagonist, despite his greediness and egotism. King Dedede lives in a castle atop a mountain with a retinue of Waddle Dees acting as his servants.

Having debuted in the series' first installment, Kirby's Dream Land, King Dedede is arguably the most recognizable character from the Kirby series besides the pink hero himself, having appeared in one form or another in nearly every game in the series (except Kirby & The Amazing Mirror and Team Kirby Clash Deluxe), though not all of those appearances are major roles. He is also the series' only character besides Kirby to have starred in his own game, namely the spin-off Dedede's Drum Dash Deluxe. He is often portrayed as a comic foil to Kirby, especially in spin-off titles. In older games, he was seldom playable, but this changed starting with Kirby 64: The Crystal Shards, with the king being playable in many of his subsequent appearances.