Thomas succeeds composer John Kennedy, who has served as chair since 2004.
"Augusta Thomas is one of the most dynamic individuals I know," said Joanne Cossa, the AMC's executive director. "The amount of energy she brings to the table is simply astonishing, and I have no doubt that she will be a great advocate for the organization and for the field at large."
Thomas has been composer in residence for the Chicago Symphony since 1997. She has written works from the New York Philharmonic, Berlin Philharmonic, Boston Symphony, and other ensembles. She taught at the Eastman School of Music in Rochester from 1993 to 2001, and currently teaches at Northwestern University in Chicago.
Founded in 1939 by composer Aaron Copland and others, the American Music Center distributes grants, publishes a newsletter and the web magazine NewMusicBox.org, and maintains an online music library and a collection of 20th-century music at the New York Public Library.