Rapp's first young adult novel, Missing the Piano, was published in 1994. After writing his second book, The Buffalo Tree, which was published in 1997, Rapp was invited to be the first author in residence at Ridgewood High School. The Buffalo Tree was censored by the Muhlenberg School Board in Reading, Pennsylvania due to its themes, graphic language and sexual content. His 2003 novel 33 Snowfish was one of Young Adult Library Services Association's Top Ten Best Books for Young Adults. He released Under the Wolf, Under the Dog in 2004.
Rapp attended the O'Neill Playwrights Conference in 1996. His play Finer Noble Gases was staged by the Eugene O'Neill Theatre in 2000, by Actors Theatre of Louisville in 2001, by Carolina Actors Studio Theatre in Charlotte in 2003, and by Rattlestick Playwrights Theater in New York City in 2004. In 2001, Nocturne was premiered by the New York Theatre Workshop. It has also been staged at by American Repertory Theater and Berkeley Repertory Theatre. His play Stone Cold Dead Serious was produced in 2002 by the American Repertory Theater.
The son of Mary Lee (née Baird; died 1997) and Douglas Rapp, Adam Rapp was born in Chicago and spent most of his youth in Joliet, Illinois.
He was a member of the band Bottomside, which released the independent CD The Element Man in September 2004. He is a member of "Less the Band", which released the album Bear in April 2006.
Rapp directed his first film, Winter Passing with Zooey Deschanel and Will Ferrell (2005), and was a creative consultant for the television show The L Word.
His first adult novel, The Year of Endless Sorrows, was released in 2006. Rapp made his graphic novel debut with the release of Ball Peen Hammer in September 2009. His second graphic novel, Decelerate Blue was published in February 2017.
While working on The L Word, Rapp left in the middle of the season to attend the Edinburgh Festival, where he directed his play, Finer Noble Gases, which won the Fringe First Award. He wrote for the 2010 season of HBO's In Treatment.
He teaches at the Yale School of Drama. In 2011, Rapp's The Metal Children was given its regional debut by Swine Palace on Louisiana State University's campus.
