Johnny Otis, the musician, bandleader, songwriter, impresario, disc jockey and talent scout who was often called “the godfather of rhythm and blues,” died on Tuesday at his home in Altadena, Calif. He was 90.

His death was confirmed by his manager, Terry Gould.

Leading a band in the late 1940s that combined the high musical standards of big band jazz with the raw urgency of gospel music and the blues, Mr. Otis played an important role in creating a new sound for a new audience of young urban blacks. Within a few years it would form the foundation of rock ’n’ roll.

With a keen ear for talent, he helped steer a long list of performers to stardom, among them Etta James, Jackie Wilson, Esther Phillips and Big Mama Thornton — whose hit recording of “Hound Dog,” made in 1952, four years before Elvis Presley’s, was produced by Mr. Otis and featured him on drums.

At Mr. Otis’s induction into the Rock and Roll Hall of Fame in 1994, Ms. James referred to him as her “guru.” (He received similar honors from the Rhythm & Blues Foundation and the Blues Foundation.)