He had worked as a bookmaker's clerk since 1938 with his father, who was first licensed as a bookmaker in 1898. Waterhouse became a barrister in 1948 but took leave of absence in 1954 after the sudden death of his brother and partner, Charles, and never returned, making bookmaking his full-time career. He worked his way on to the 'rails' (the Australian higher-class, higher-stake betting ring at a racetrack, as compared to bookmakers of the 'paddock'), and rose to be reputed the world's biggest bookmaker and gambler in 1968. He engaged in betting duels with giant punters such as Frank Duval (Hong Kong Tiger), Filipe Ismael (The Filipino Fireball) and Ray Hopkins. A man of large stature, he was dubbed 'Big Bill' and 'king of the bookies', remaining at the top for over 20 years. Waterhouse often turned over more than the
tote. Waterhouse was cleared of rumours surrounding the doping of
Melbourne Cup co-favourite,
Big Philou in 1969, when it was shown by
Australian Jockey Club (AJC) officials he was not working on the race, by then being a Sydney bookmaker and did not stand to lose on Big Philou in the doubles business run by his staff. and the AJC revoked their licenses, before waiting for the results of the Queensland police inquiry into the ring-in. However, it was never alleged they had any involvement in the actual ring-in. ==Interests outside bookmaking==