At age 5, William Miller arrived in Victoria, Australia with his family.
From 1862 to 1869, Miller worked for the Melbourne and Hobson's Bay Railway Company as station-master and telegraph instructor.Miller became proprietor of the Melbourne Gymnasium, and instructor to some the leading Melbourne schools.
Miller won the Australian broadsword championship in 1872.
In the US from 1874 to 1880 he defeated cosmopolitan champions in boxing and wrestling, out of 72 matches, he had 55 wins and 11 draws.
In 1879 he defeated Duncan Ross walking over 102 miles (164 km) in 24 hours and drew with the champion weight-lifter Richard Pennell, both lifting 1550 lbs.