Second Banana is a term that has been around a really long time that meant "second billing" in an acting company. It's most often applied to comedians or comedies now; in such cases it's the supporting comedian, who may also be the Straight Man. Depending on the story he could be either the victim of the primary comedian's (deliberate or unwitting) antics or the more successful one, who sits back and snarks at the star's foolishness. The Second Banana may no longer actually get second billing.
In terms of characters, it is most often the sidekick, best friend, or co-worker of the protagonist.
Compare The Lancer.
- Art Carney was Second Banana to Jackie Gleason in The Honeymooners.
- In The Andy Griffith Show, and later in Mayberry R.F.D., Don Knotts was the second banana.
- Neil Patrick Harris's Barney Stinson is the second banana on How I Met Your Mother.
- Vivian Vance was usually Lucille Ball's second banana in I Love Lucy and The Lucy Desi Comedy Hour.
- In Mystery Science Theater 3000, TV's Frank (Frank Conniff) was second banana to Dr. Clayton Forrester (Trace Beaulieu). This even got lampshaded—when Frank left the show, he did so by ascending to Second Banana Heaven.
- Looney Tunes being the most iconic source of animated comedy, often centered on comedy and show business has quite a few examples:
- Porky Pig was the studio's first major star but soon became the Second Banana and the Straight Man to the much wackier, egotistical and denser Daffy Duck. In-universe he was most often conned, tormented and/or bossed around by Daffy, depending on the short. At times all three together. He usually had the last laugh though, thanks to either paying him back in kind, or showing that he was more capable in all perilous situations.
- There was a character (a mouse) actually named Second Banana in some Warner Brothers cartoons, and in some Gold Key comics based on them. He was the sidekick of Merlin the Magic Mouse, a vaudeville-style stage magician.