Westerfeld was born in Texas. As a child he moved to California and Connecticut for his father Lloyd's job as a computer programmer. He saw his dad working with planes, submarines, and the Apollo missions.
Westerfeld graduated from Vassar College with a B.A. in Philosophy in 1985. He began composing music as a teenager and composes music for modern dance. In 2001, Westerfeld married the Australian author Justine Larbalestier.
He now divides his time between Sydney, Australia and New York City.
Westerfeld is well known for the Uglies series. He also wrote The Risen Empire and The Killing of Worlds, parts one and two of the same work, originally titled Succession, published in the UK in 2005 under the title The Risen Empire.
Westerfeld has written a manga series called Shay's Story. He has also written the Leviathan trilogy, consisting of Leviathan, Behemoth, Goliath, and The Manual of Aeronautics, an illustrated guide to the Leviathan series.
Westerfeld has revealed on his blog that he is currently working on his next novel, to be titled Afterworlds. On March 12, 2013, he shared, “Afterworlds is going to be a long piece of work, with two novels wrapped into one in a strange and mystical way. I’m maybe halfway done, so the novel isn’t going to be in anyone’s hands until late next year.”
Several of his novels have been optioned for films. So Yesterday has been optioned to be made into a film by one of the producers of Fahrenheit 9/11 and Bowling for Columbine. However, this option 'slowly died', as Scott Westerfeld wrote on his blog. The Uglies series was optioned in 2006 by Twentieth Century Fox as a possible film series.