In addition to Jenni, his teachers have included Henri Lazarof, Lou Harrison, Richard Hervig, Jacob Druckman, Hans Werner Henze, and Martin Bresnick.

[7] In 1999 he collaborated with composers Julia Wolfe and Michael Gordon and librettist/illustrator Ben Katchor on the composition of the "comic strip opera" The Carbon Copy Building.

Lang, Wolfe and Gordon subsequently collaborated with librettist Deborah Artman 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 also 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.

In 2017 Chinese singer Gong Linna premiered Cloud River Mountain, written by the three Bang on a Can composers in addition to Lao Luo.

Its U.S. west coast premiere was directed by Robert Geary and performed by the San Francisco Choral Society, Volti, the Piedmont Children's Choir, and the Leah Stein Dance Company in April 2013 at the Kezar Pavilion.

Lang was awarded the 2008 Pulitzer Prize in music for his piece The Little Match Girl Passion, composed in 2007 for Paul Hillier and his Theatre of Voices.

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.

[13] The recording by Theatre of Voices and Paul Hillier of The Little Match Girl Passion on Harmonia Mundi received a 2010 Grammy Award for Best Small Ensemble Performance.

[14] Lang composed this song cycle – a commission from Carnegie Hall and Stanford Lively Arts, premiered at both in late January, 2012[15] – as a companion piece to the little match girl passion.

The part of Death was sung by Shara Worden of My Brightest Diamond; the instrumentalists included Bryce Dessner of The National (band) on guitar, Nico Muhly on piano, and Owen Pallett on violin and voice.

The opera includes these anonymous confessions, which are whispered by soprano Tony Arnold, while four instrumentalists from the International Contemporary Ensemble never play above a hush.

It begins with the confession and execution of an English murderess and follows the quest of the anatomist, searching for signs of evil within her body, including an aria for the corpse.

[21] The original cast recording was released on Cantaloupe Music with Marc Kudisch, Peabody Southwell, Robert Osborne, Timur, International Contemporary Ensemble, and conducted by Christopher Rountree.

[27] They were "commissioned by Konzerthaus Dortmund, for the baritone Benjamin Appl, specifically to go on a program with Schubert's great song cycle Die Schöne Müllerin".

In Lang's 2015 film score, Youth for Italian director Paolo Sorrentino, he also provided the music for the protagonist, a composer and conductor played by Michael Caine.

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) featuring performances by Audrey Riley, A Change of Light, and Lisa Moore.