Lumpy Space King makes his first appearance in "Trouble in Lumpy Space". He is Lumpy Space Princess's father and the husband of Lumpy Space Queen. In the episode, he is seen driving home and yelling at his daughter for bringing "smooth people" into their world. He later bans Lumpy Space Princess from using the family car because she yelled at her mother. He seems to refer to LSP only as "daughter". He also makes a brief appearance at the end of "The Duke", during the Grand Meeting of Ooo Royalty, and in "The Eyes", dancing at LSP's quinceañera. He appears to be over-protective and strict. He once referred to their car as "the royal car" despite that evidently, there is nothing noticeably special about it.
Lumpy Space King has had two slightly different designs throughout the series. His appearance is that of a purple Lumpy Space Person. He wears black-rimmed glasses, and, like LSP, has a gold star on his forehead, which probably represents royalty in Lumpy Space. This may also be a kind of indicator that his floating powers are active, because when LSP "turned off" her floating, her own star turned dark. He is conjoined with Lumpy Space Queen. The reason for this is that when Lumpy Space People marry, they become fused together. In his original design, he is scruffy and slightly chubby-looking, with long, stringy hair, a green, striped tie, almond-shaped glasses and chin stubble.
- "The Prince Who Wanted Everything" (gender-swapped version)
- "Trouble in Lumpy Space" (debut)
- "The Duke"
- "The Eyes"
- "The Monster"
- "Skyhooks II" (flashback, no lines]]
Daughter! Have you brought smooth people into our domain?!
You've made your mother cry for the last time, Daughter! You are hereby banned from using the royal car!