Webb was born on August 15, 1946 in Elk City, Oklahoma. His father, Robert Lee Webb, was a Baptist minister and alumnus of the United States Marine Corps who presided over rural churches in southwestern Oklahoma and west Texas. With his mother's encouragement, Webb learned piano and organ, and by the age of 12 was playing in the choir of his father's churches, accompanied by his father on guitar and his mother on accordion. Webb grew up in a conservative religious home where his father restricted radio listening to country music and white gospel.