Background characters are, as the name implies, characters that appear in the background of some stages, they will appear in a stage that correspond to their home universe (i.e Shy Guys appear in Yoshi's Island). Note that background characters shouldn't be confused with stage hazards.
In Super Smash Bros.
Congo Jungle
- Necky appears flying in the background.
Dream Land
- King Dedede and Bronco Burt appear flying in the background.
Mushroom Kingdom
- Many classic enemies from Super Mario Bros are seen in the background.
Planet Zebes
- Several enemy sprites ripped directly from Super Metroid, including Ridley, can be seen flying around.
Saffron City
- Several flying and bird type Pokémon, including but not limited to, Pidgey, Fearow, and Butterfree fly across the skyline.
Yoshi's Island
In Super Smash Bros. Melee
Brinstar
- A Chozo statue on the main platform comes to life and briefly walks before settling down into its original position.
Brinstar Depths
- Kraid emerges from the lava and swipes at the stage, turning it clockwise or counter-clockwise.
Fourside
- A U.F.O which can be boarded hovers in close proximity to the Monotoli building.
Yoshi's Story
- Shy Guys fly over the stage, this time holding food.
- Pak E. Derm can be seen walking behind the scenery.
Jungle Japes
- Cranky Kong is seen walking back and forth in his cottage and rocking in his chair at various times.
Yoshi's Island
- A Lakitu and a Banzai Bill fly around in the background.
Mushroom Kingdom 2
- A Birdo moves in from either the left or right and shoots eggs into the battlefield and a Pidgit flies in on its magic carpet. Only the Birdo can be KO'ed.
Onett
- The meteor from the beginning of Earthbound can be seen pulsating at the top of the hill, while one of the car hazards is the Runaway 5 tour bus.
In Super Smash Bros. Brawl
New Pork City
- A statue of Pokey Minch from EarthBound appears in the right side of the stage.
Lylat Cruise
- Multiple ships appear battling in the background.
Smashville
- Villagers from Animal Crossing appear in the background.
Yoshi's Island
- For a third time, Shy Guys appear in the background.
Frigate Orpheon
- The Parasite Queen, the first boss of Metroid Prime, appears in the background in Frigate Orpheon.
Pokémon Stadium 2
- Electivire, Drifloon, Hoppip, Skarmory, Cubone and Dugtrio all appear in the background of the various elemental transformations of the stage.
Green Hill Zone
Great Sea
- The King of Red Lions, appears on the background of the stage.