Fadden was born in Ingham, Queensland, on 13 April 1894. He was the eldest of ten children – seven sons and three daughters – born to Annie (née Moorhead) and Richard John Fadden. His parents were both born in Ireland, his mother in County Tyrone and his father in County Galway. Fadden moved to Walkerston at a young age, where his father was officer-in-charge of the local police station. He had a "typical country childhood", but suffered the deaths of three of his younger siblings in separate accidents. Fadden received his only formal education at the Walkerston State School, except for a brief period at Te Kowai while his usual school was being renovated. His first jobs included collecting cane beetles and performing sound effects at the local cinema. Fadden left school at the age of 15 and began working as a "billy boy" (odd-job man) on a cane-cutting gang at Pleystowe. He later secured an indoor job as an office boy at the Pleystowe Sugar Mill, where his colleagues include two future Labor MPs – Maurice Hynes and George Martens. In his spare time, he developed an interest in the theatre, both as a performer and treasurer of the local company.