Herb Jeffries, who sang with Duke Ellington and starred in early black westerns as a singing cowboy known as “the Bronze Buckaroo” — a nickname that evoked his malleable racial identity — died on Sunday in West Hills, Calif. He was believed to be 100.

The cause was heart failure, said Raymond Strait, a writer who had worked on Mr. Jeffries’s autobiography with him.

Mr. Jeffries used to say: “I’m a chameleon.” The label applied on many levels.

Over the course of his century, he changed his name, altered his age, married five women and stretched his vocal range from near falsetto to something closer to a Bing Crosby baritone. He shifted from jazz to country and back again, and from concert stages to movie theaters to television sets and back again.

He sang with Earl Hines and his orchestra in the early 1930s. He starred in “Harlem on the Prairie,” a black western released in 1937, and its several sequels. By 1940, he was singing with the Ellington orchestra and soon had a hit single, “Flamingo,” released in 1941, which sold more than 14 million copies. (His name had been Herbert Jeffrey, but the credits on the record mistakenly called him Jeffries, so he renamed himself to match the typo.)