Louie is the main character of E.B. White's book The Trumpet of the Swan and its film adaption (in which his name is respelled with the "S" being replaced by an "E": "Louie"). Unlike his older brothers and sisters, Louie has no voice. This makes his parents worry that it means he won't find a mate. Although he is mute, he learns from 11-year-old Sam Beaver how to write. Also, being known as a "trumpeter swan", he learns how to play a trumpet. He is in love with a swan named Serena (who is voiced by Reese Witherspoon in the film), but cannot attract her attention. Although he doesn't speak (aloud) in the book or film, his voice-over is dubbed by Dee Bradley Baker in the latter.
- Louie will meet Pooh, Ash, Littlefoot, Mickey, Alex, SpongeBob and their friends in Winnie the Pooh and The Trumpet of the Swan.
- Louie will meet Thomas and his friends in Thomas the Tank Engine and The Trumpet of the Swan.
- Louie met Roary the Racing Car, Theodore Tugboat and their friends in Roary, Theodore and The Trumpet of the Swan.