Siggs was born into a sporting family with his brother, Keith, representing Queensland in school level hockey and his sister, Sybil, representing Queensland in women's baseball. In his youth he played basketball, hockey, and cricket being selected for the state schoolboys' teams in hockey and cricket from 1933 to 1935. He attended Valley School where he was first noticed as a talented cricketer and the Valley cricket club unsuccessfully attempted to recruit him for district cricket in the early 1930s.
