Jim Stewart, a part-time fiddle player who became a soul music hitmaker as the co-founder of Stax Records, the trailblazing Memphis label that helped launch the careers of 1960s and ’70s artists including Otis Redding, Isaac Hayes, Sam & Dave and the Staple Singers, died Dec. 5 at a hospital in Memphis. He was 92.

His death was confirmed by Tim Sampson, a spokesman for the Soulsville Foundation, which operates the Stax Museum of American Soul Music in Memphis. He said that Mr. Stewart had been ill but did not cite a specific cause.

As an executive, producer and engineer, Mr. Stewart was a driving force behind the Tennessee music company, which trailed only Motown Records as the country’s top soul label. Its records came to define the “Memphis sound,” a sultry fusion of Southern soul, blues and gospel epitomized by Stax artists including Redding, Wilson Pickett, Rufus and Carla Thomas, and the label’s house band, Booker T. & the M.G.’s.

Mr. Stewart later acknowledged that he “knew nothing” about music publishing, copyright issues or the mechanics of how to get a record pressed when he started the label in 1957. But he loved country music — especially the Western swing of Texas fiddler Bob Wills, whom he emulated while playing in bands — and hoped to replicate the success of Memphis producer Sam Phillips, the Sun Records founder who produced recordings by Elvis Presley and Roy Orbison.

Working out of his wife’s uncle’s two-car garage, Mr. Stewart recorded country and rockabilly songs with backing from his older sister Estelle Axton, who joined him as a co-founder. But after they moved the company into a former movie theater on the south side of Memphis in 1960, he began recording R&B songs by local musicians, embracing soul music in full after cutting a regional hit, “Cause I Love You,” by Memphis DJ Rufus Thomas and his teenage daughter Carla.

“It was like a blind man who suddenly gained his sight,” Mr. Stewart later recalled. “You don’t want to go back; you don’t even look back.” Or as he put it in an interview for “Respect Yourself,” a 2007 PBS documentary that was later adapted into a book by Robert Gordon: “The wind blew in, and we were smart enough not to fight it.”