He was also known as "The Champ", due to his exquisite riding skills. Perhaps his most famous victory was defeating Phar Lap on Mollison in the 1929 Chelmsford Stakes. He officially retired from riding in 1959.
Cook was posthumously inducted in the Australian Racing Hall of Fame in 2002.
Billy earned the nickname "Last-Race Cookie" following his riding of the winner in the last race 13 Saturdays in succession in Sydney. He won six Sydney jockeys" premierships during a distinguished career riding in Australia and overseas. Some of the achievements during his career included winning the 1941 and 1945 Melbourne Cups (Skipton and Rainbird), the 1930 Caulfield Cup (Amounis), the 1953 Sydney Cup (Carioca), and the 1954 Central Bank Fisher Plate (Rising Fast).
