In 2008 he joined the Yale School of Music composition faculty.
Lang's music is informed by modernism, minimalism, and rock - and can perhaps be best described as post-minimalist or totalism. His music can be in turn comic, abrasive, and soothing, and it usually retains elements of conceptualism. He sometimes gives his concert pieces strange and even iconoclastic titles such as Eating Living Monkeys (1985) and Bonehead (1990).
He was a major contributor to the music performed by the Kronos Quartet in Requiem for a Dream being the arranger in studio. He is also well known for his work with Édouard Lock and La La La Human Steps.
In 1999 he collaborated with composers Julia Wolfe and Michael Gordon and librettist/illustrator Ben Katchor in the composition of the "comic strip opera" The Carbon Copy Building. The production won an Obie Award for Best New American Production. Lang, Wolfe and Gordon subsequently collaborated on the 'oratorio' Lost Objects, the recording of which was released in summer 2001 (Teldec New Line). Their next collaborative project was Shelter, a multi-media work with librettist Deborah Artman,for the Scandinavian vocal group Trio Mediaeval and the German ensemble musikFabrik, which was performed in Germany and the U.S. in 2005.
Also in 1999, Lang based his opera The Difficulty of Crossing a Field on a short story by Ambrose Bierce, about an Alabama planter named Williamson who purportedly vanished while walking across a field in 1854. (Bierce's story reoccurs in urban-legend form, in which, coincidentally, the vanished man is often given the name David Lang.)
Lang was awarded the 2008 Pulitzer Prize in music for his piece The Little Match Girl Passion, composed in 2007. The piece, based on Hans Christian Andersen's fable "The Little Match Girl" and inspired by Bach's St. Matthew Passion, was co-commissioned by the Carnegie Hall Corporation and The Perth Theater and Concert Hall and premiered on October 25, 2007 in Zankel Hall in New York City. Tim Page of the Washington Post wrote that "I don't think that I've ever been so moved by a new...composition as I was by David Lang's The Little Match Girl Passion, which is unlike any music I know."
Lang's music has been released on the Argo/Decca, BMG, Cantaloupe Music, Chandos, CRI, Point, and Sony Classical labels. His solo albums for Cantaloupe include "The Passing Measures" (2001) with the Birmingham Contemporary Music Group, "Child" (2003) played by Sentieri Selvaggi, and "Elevated" (2005) featuringing performances by Audrey Riley and A Change of Light, and Lisa Moore. His music has also been represented on recordings by Icebreaker, So Percussion, Bang on a Can All Stars and Evan Ziporyn. His scores are published by Red Poppy Music (available from G. Schirmer, Inc.)