Tropper was born in the Riverdale section of the Bronx, New York City. He studied English as an undergraduate at Yeshiva University and received a master's degree in creative writing at New York University, after which he spent eight years running a Manhattan-based company that manufactured displays for jewelry companies. He wrote at night and on weekends, ultimately publishing his first novel, Plan B, which attracted the attention of an agent, allowing him to leave his job and become a full-time writer. Four of Tropper's five books have been optioned at auction within a week of publication (The Book of Joe, How to Talk to a Widower, Everything Changes and This Is Where I Leave You).
The themes of his books appear to stem from his personal experiences: they deal with topics such as being single, growing up, getting married, being married, getting divorced, and living in suburbia. Tropper's hometown of New Rochelle in Westchester County, New York, is a main source of inspiration when creating the characters and settings in his books.
How to Talk to a Widower was a 2007 selection for The Richard and Judy Show in the United Kingdom. Everything Changes was a Booksense selection. Three of Tropper's books are currently being adapted into movies. Tropper cowrote the film adaptation of The Book of Joe with Ed Burns, who will direct.This Is Where I Leave You was published in August 2009 and was a New York Times bestseller. It was made into the 2014 film of the same name. Tropper's most recent novel, One Last Thing Before I Go, was published in August 2012. The novel was optioned by Paramount Pictures for J. J. Abrams.
Tropper, together with David Schickler, created the 2013 television series Banshee, which premiered in January on Cinemax; Tropper serves as an executive producer on the show.