Jerry is Jack's relative and the main protagonist of Elmo's Country 1/2. He is also the man responsible for creating a prototype version of Elmo named "Proto-Elmo".
(Jerry was originally referred to as "Worker" or "The Worker" in the screenplay.) Jerry was first seen trying to convince the Boss to create an Elmo Robot, but the Boss didn't like this idea and fired him. Jerry goes home, revealing that he has been working on a prototype Elmo robot. He manages to finish work on it, but accidentally causes the slavery memory cube to turn into Anti-Elmo. Anti-Elmo attacks Elmo, but Elmo fires a blaster gun at Anti-Elmo, destroying the factory and scattering the animatronics to various places around the city. Everyone except Jerry is killed, and he walks out of the factory after realizing what happened. It's unknown what happens after that.
It's unknown what Jerry looks like, as the script never describes his appearance. But it's assumed that he's a young man.
Jerry is very optimistic, and likes to build machines. Not much else is known about his personality.
Jerry has demonstrated the ability to build robots. Not much else is known.