Bill France Sr. was a pivotal figure in the history of NASCAR (National Association for Stock Car Auto Racing). He founded NASCAR in 1948 and played a crucial role in shaping it into one of the most popular motorsports in the United States. France Sr. was instrumental in establishing NASCAR's rules and structure, as well as promoting the sport nationwide. His vision and leadership were fundamental in NASCAR's growth from a regional pastime to a nationally recognized sport with a large fan base.