Wolfman Jack, the rock-and-roll disk jockey whose unmistakable raspy voice and on-the-air howls brought him something of a cult following as one of America's best-known radio personalities, died yesterday at his home in Belvidere, N.C. He was 57.

The cause was a heart attack, said his daughter, Joy Renee Smith.

He was a radio-show host right up until his death, broadcasting his last "oldies but goodies" show Friday night from a Planet Hollywood restaurant in Washington, D.C. Just before his death he returned home from a 20-day tour to promote his autobiography, "Have Mercy: Confessions of the Original Rock-and-Roll Animal," published by Warner Books.

He was born Robert Smith in Brooklyn on Jan. 21, 1938, and for a couple of years in 1960 and 1961 he was Daddy Jules on WTID in Norfolk, Va.

But he cascaded to fame as Wolfman Jack, a faceless hero on the AM airwaves and a pioneer of the peculiar genre called border radio, because it was broadcast from just over the border in Mexico. He was among a group of border disk jockeys in the early 1960's with names like Hound Dog and Huggy Boy, and he had his name legally changed.