Wentz was born Peter Lewis Kingston Wentz III, in Wilmette, Illinois, an affluent suburb of Chicago. He is the son of Dale (nee Lewis), a high school admissions counselor, and Pete Wentz II, an attorney. He is of English and German descent on his father's side and Afro-Jamaican on his mother's side. He has a younger sister, Hillary, and a younger brother, Andrew.

Wentz has written a book entitled The Boy With the Thorn in His Side, a story based on nightmares he had as a child. The title is a reference to a track on The Smiths' album The Queen Is Dead. Wentz explained that writing books serves as another mode of self-expression other than songwriting: "My inspiration and my ideas don't begin and end at the beginning and the ending of a song. It is too limiting." It was reported that he was to publish another book, entitled Rainy Day Kids, but years went by without any word on the book's progress, and Wentz even expressed on his  Twitter account that he didn't think it would ever come to fruition. However, in February 2012, he posted a photo on his personal blog of what appeared to be a rough draft of the book's manuscript, explaining that he was currently in the process of editing Rainy Day Kids and that it would be 40-50 pages longer than he originally expected. On December 13, 2012, Wentz revealed the cover for the book, now titled Gray, on his personal blog. The book, which was written with MTV News writer and former FNMTV co-host James Montgomery, was released on February 26, 2013.  In June 2009, it was announced that Wentz was working on a five-issue comic book mini-series called Fall Out Toy Works, to be published by Image Comics. The idea was conceived by Wentz and designer Darren Romanelli. The plot is loosely based on the Fall Out Boy song "Tiffany Blews" and focuses on "a mysterious toymaker, a cyborg gal named Tiffany and a kid in a bear suit that looks lifted from the cover of Fall Out Boy's Folie a Deux." With writing by Brett Lewis, and art by Sam Basri, the first issue was released on September 2, 2009. Answer this question using a quote from the following article:

What did he try next
Rainy Day Kids and that it would be 40-50 pages longer than he originally expected.