Samuel Henry John Worthington was born to English parents in Godalming, Surrey, in South East England. They moved to Perth, Western Australia, when he was 6 months old. He was raised in Warnbro, a suburb of Rockingham. His mother, Jeanne J. Worthington (née Martyn), is a housewife, and his father, Ronald W. Worthington, is a power plant labourer. He has a sister, Lucinda.
Worthington attended Rockingham Senior High School and John Curtin College of the Arts, a high school specialising in the dramatic arts, located in Fremantle, Western Australia, where he studied drama but did not graduate. When he left the college, his father gave him $400 and sent him on a one-way trip to Cairns, Queensland, telling him to "work his way home". He began working on construction and odd jobs, eventually settling in Sydney. At the age of 19, while working as a bricklayer, he auditioned for the National Institute of Dramatic Art and was accepted with a scholarship.
