Jerry and Liz Trainor grew up in San Diego, Scripps Ranch. They attended the University of San Diego High School.

Jerry Trainor began his acting career as Crazy Steve in 2004. Jerry played in an episode of Drake & Josh on Nickelodeon.

Jerry studied drama at the University of California where he graduated with a Bachelor's degree in Fine Arts. Jerry also studied improvisation at The Groundlings school in Los Angeles. Before becoming an actor, Jerry worked at San Diego SeaWorld. 

Although Jerry majored in acting at the University of California, he participated actively in high school theatrical programs such as Sugar, The Matchmaker, Guys & Dolls, The Pajama Game, and Up the Down Staircase. He made appearances in the movies.

The actor almost became an architect before coming into movies. He was an excellent math student in high school.

His popularity rose In the teen sitcom iCarly in the role of Spencer Shay, for which he won three Kids' Choice Awards. Additionally, he played Dudley Puppy in T.U.F.F. Puppy, for which he was nominated for a Daytime Emmy Award.

Besides acting, Jerry enjoys collecting vinyl records and comic books and spending time with his rescue dogs.