While still in college they wrote Edges, a song cycle about the trials and tribulations of moving into adulthood and the search for meaning. Premiering in Ann Arbor, Michigan on April 3, 2005, it proved popular on social media and within several years it had over 200 productions worldwide, with countries including Australia, South Africa, Denmark, France, South Korea, the United Kingdom, Canada, the Philippines, and the United States.

Their New York premiere on May 14, 2006 was a benefit concert of original songs titled Become: The Music of Pasek & Paul. Presented by Jamie McGonnigal, performers included Gavin Creel, Cheyenne Jackson, Celia Keenan-Bolger, Jesse Tyler Ferguson, and Steven Pasquale. They contributed to the 2006 off-Broadway musical White Noise: A Cautionary Musical, which won Talkin' Broadway's 2006 Summer Theatre Festival Citation for Outstanding Original Score.

The duo have written original music for several television shows. As of 2007, Pasek and Paul were writing music for the Disney Channel show Johnny and the Sprites, with songs used in six episodes and for one story in the season's premiere.

Pasek and Paul wrote the score to the musical adaptation of Roald Dahl's James and the Giant Peach, which premiered in 2010 through Goodspeed Musicals. Other works include If You Give A Pig A Pancake (2010) and Duck For President for Theatreworks USA, and Dr. Williams, written for the Orchard Project's 24 Hour Musicals benefit. The show starred Jesse Tyler Ferguson and Cheyenne Jackson. Pasek and Paul were featured in the 2011 documentary film One Night Stand about the process. They wrote the lyrics and music to the 2012 musical Dogfight, also contributing to A Christmas Story, The Musical, which was nominated for a Tony Award in 2013 for Best Original Score.

Their original material was featured on season 2 of NBC's Smash in 2013, and have risen to the Top 25 on the iTunes Pop Charts.

They wrote the music and lyrics to their musical Dear Evan Hansen, which was inspired by a traumatic incident in Pasek's life, the death of a high school student, and based on a book by Steven Levenson. Directed by Michael Greif and starring Ben Platt, it premiered at the Arena Stage in Washington, D.C. on July 30, 2015. It premeiered Off-Broadway debut in March 2016 at the Second Stage Theatre, and on Broadway on November 14, 2016, opening three weeks later at the Music Box Theatre. At the 71st Tony Awards, it was nominated for nine awards including Best Musical, Best Score, Best Book of a Musical, and Best Actor in a Musical for Platt. It won six awards including Best Musical and Best Original Score for the duo. At the 2018 Grammy Awards, Dear Evan Hansen won Best Musical Theater Album. The musical received the Edgerton Foundation New Play Award and the 2016 Obie Award for Musical Theatre.

Paul's alma mater is the University of Michigan and Staples High School. Paul is married; he and his wife have a daughter, born in 2016.

Pasek and Paul wrote the songs for the 2017 musical drama film The Greatest Showman. About the Barnum & Bailey Circus, the film premiered on December 8, 2017. The duo's song "This Is Me" won a Golden Globe for Best Original Song and was nominated for Best Original Song at the 90th Academy Awards.

Pasek and Paul are writing songs for Disney's upcoming live-action film adaptation of Snow White and the Seven Dwarfs. In collaboration with Alan Menken, Pasek and Paul will also be writing new songs for Disney's 2019 live-action film adaptation of Aladdin. The film will also include original 1992 song compositions written by Menken, Howard Ashman, and Tim Rice. The duo has also been selected to write songs for Foster, the working title of an animated film from Blue Sky Studios. It is projected to reach theaters in 2021.