Tinny serves as the short's protagonist. Throughout the short, he encounters a human baby named "Billy" who chases him across the room. During the short, Tinny hides under a couch, causing Billy to cry that he has no toy to play with. Feeling for Billy's emotion, Tinny decides to play with him after realizing the wrong actions he did.
In the early draft, Tinny was a toy that was bought by a man for his son's birthday party. While on a road trip with the family, he ends up getting left behind at a gas station and found by a garbage collector. While in the back of the truck, Tinny befriends a ventriloquist dummy (who would eventually transform into Woody) and the two go on an adventure that ended with them landing in a kindergarten classroom where they realize that they can be played with forever and not have to worry about being outgrown by the children.
When the setting was moved to a children's bedroom, the filmmakers realized that Tinny was not the ideal new toy that kids would want and he was eventually changed to the much more appropriate Buzz Lightyear.
Tinny (now older yet still has his chipper personality) is the "owner" of the club hidden under the Tiki Party pinball machine at the Antique Store, where all the antique toys hang out. This makes it the first time that the character appears in a physical manner in a Toy Story film, not counting his cameo appearance in Toy Story 2 through archived footage.
- In the unmade television special A Tin Toy Christmas, it would have been revealed that Tinny belonged to a set of tin toys in the 1940s.
- The directors of Toy Story 4 have confirmed that the Tinny seen in Toy Story 4 is the same one from the Tin Toy short, meaning that his former owner, Billy, eventually grew up and donated him to the Antique Store (this also means he donated the rest of his toys to Sunnyside Daycare, as they are spotted hiding under a table in the Caterpillar Room in Toy Story 3).
- Tinny can be seen in the short Lifted underneath Ernie's bed.