Bud Smith is the son in the Smith Family. He appears as if he were a tween. He has green hair, an overbite, an unusually long, pointed nose that protrudes from the side of his face, a red and white shirt and braces. He made his first appearance in the episode Supper Villain. The reason he hates the Powerpuff Girls is because "he hates everything." He also seemed to despise his dad, until after Harold became a super villain in a later episode.
Bud Smith is shown to be eight or nine years old. He says he "hates everything", including his dad — until one night when his mother invites the Powerpuff girls and the Professor over for dinner. It is then that his father finally reveals himself as Super Villain Harold Smith, much to Bud's delight.
After a food fight begins and when the police arrives to arrest Harold, Bud's mother, Maryanne, is shown to be upset and angry for the girls "ruining" her dinner. Bud is first seen in the episode's sequel when he runs up to his family declaring that he hates everything, which becomes one of his famous quotes in the process.
He is then seen siding with the rest of his family to destroy the Powerpuff Girls, starting with ruining their house. Yet when this attempt fails, Bud and his family are chasing after the Powerpuff Girls, which leads to a defeat; Bud and his family are arrested.
- It is unknown what happens to Bud after he and his family are put in jail at the end of Just Desserts. He and his family are never seen in the show or heard from after then. Their house became vacant and a girl named Robin moved in with her family.
- Bud along with his mother and father (though not together and no Julie) appeared in the Powerpuff Girls issue #5 "Little" comic magazine cover with other Townsville citizens such as Ms. Keane, Princess Morbucks, Ms Bellum, Mayor, Professor Utonium, Robin Snyder (whom he happens to be the closest too by a few inches behind her) and other much more well known characters from the show.
- Bud was voiced by the late Christine Cavanaugh, who voiced Dexter on Dexter's Lab and also voiced Bunny in the episode "Twisted Sister".
- Bud was the original name for Buttercup before Miles Thompson, a friend of Craig McCracken, came up with her current name when the original name didn't work and Craig tried to think of a better name for her.
- "This family stinks!"
- "No one understands me!"
- "Leave me alone!"
- "That's right. You really took care of Mojo Jojo, huh?"
- "Okay dad, lets talk about your amazing day. How many mustard jars did you fill?"
- "They're probably all sad."