Carter's assistant, Virgil Blackwell, confirmed his death to The Washington Post, but did not disclose the cause.
Igor Stravinsky praised his fellow composer, who began succeeding in his music career when he was 40, for creating what he said was the first American masterpiece -- "Double Concerto for Harpsichord, Piano and Two Chamber Orchestras" -- in 1961.
He won his first Pulitzer Prize in 1960 for "String Quartet No. 2" and his second for "String Quartet No. 3" in 1973.
The Post said the New York native continued composing until shortly before his death, with his works ranging from ballets to vocal, instrumental, chamber and orchestral pieces.