Jeff Kinney was born and raised in Maryland, a middle child in his family much like the protagonist Greg in Diary of a Wimpy Kid. Kinney attended the University of Maryland, College Park and developed an interest in being a professional comic artist while writing the strip Idgoof for his school's newspaper The Diamondback. While he wasn't able to translate that into a career in comics at the time, the idea stuck with Kinney.
In 1998 he developed the idea for the main character of Diary of a Wimpy Kid, Greg. He'd continue to develop Greg for several years, until finally publishing the first Diary of a Wimpy Kid comics on Funbrain.com in 2004. The comics earned popularity quickly, with the first Diary of a Wimpy Kid graphic novel getting printed in 2007. Since then, Kinney has released a new installment in the Diary of a Wimpy Kid series every year. The books have been adapted into films, and Kinney has also written two books which are spin-offs of the movies, and in 2019 he published a novel written from the perspective of Greg's best friend Rowley, called Diary of an Awesome Friendly Kid: Rowley Jefferson's Journal.
Kinney has built a career around the Diary of a Wimpy Kid franchise, including his executive producer roles on the four Diary of a Wimpy Kid movies that have come out so far. But he has also branched out into other projects. In 2007, he started the website Poptropica, which is an educational gaming website for young children. He has also opened a book store in his current hometown of Plainville, Massachusetts called An Unlikely Story.