Larry. In Season 6, after his retirement, Jerry returns to the Parks Department full-time, and wants to start off fresh. Part of that means that his co-workers call him by his real name, "Garry," which he screws up by accidentally calling himself Larry. Poor guy never saw it coming, but thus, Larry Gengurch was born.

When did they start calling Jerry Larry?

From the season 6 episode "Doppelgängers" everyone starts calling him "Larry Gengurch" at the encouragement of April, a situation "Larry" meekly accepts with little protest.

Why is Gayle with Jerry?

Behind the scenes, however, there's an actual reason why Gayle married Jerry. As the characters were incredibly mean to Jerry all the time and Jim O'Heir was very loved by the cast and crew, the writers decided to compensate all the bullying thrown at Jerry by giving him the perfect family.