Born August 2, 1976, in Godalming, Surrey, England; Samuel Henry J. "Sam" Worthington was born of his parents – his father, Ronald a power plant employee and his mother, a homemaker cared for him and his sister – in Warnbro, a suburb of Rockingham near Perth, Australia.
He attended John Curtin College of the Arts, but school was never a priority for him as he dropped out at 17, though he did show his first inkling of interest in the arts while in high school. He worked construction and odd jobs, eventually settling in Sydney. He was 19 and working as a bricklayer when he auditioned for the National Institute of Dramatic Art (NIDA) and was accepted, with scholarship; where he gained valuable training from the Institute, graduating in 1998 at the age of 22.