She had 2 Strictly Stock (now Sprint Cup) starts. She raced against her brothers at NASCAR's second event ever on July 10 1949 at the Daytona Beach Road Course. The event was the first to feature a brother and a sister, and the only NASCAR event to feature four siblings. Ethel beat Fonty and Bob by finishing eleventh (her career high), and Tim finished second. She made her only other career Cup start at Langley Speedway and finished 44th. Both events featured three female drivers (Sara Christian and Louise Smith).
In June, 1949, she entered a racing competition in Florida, competing against 57 men drivers. She finished in 8th place.
On August 7, 1949, Ethel Mobley became the first female racecar driver to compete against men in the state of Georgia when she entered a race at Central City Park Speedway in Macon, Georgia. She was rated as the top woman driver in the southeastern United States,. having won many competitions in all-women races.