Hume was born in England, the second son of James Hume. When he was three the family emigrated to Dunedin, New Zealand, where he was educated at Otago Boys' High School and studied law at the University of Otago. He was admitted to the New Zealand bar in 1885. Shortly after graduation Hume relocated to Melbourne, Australia, where he obtained a job as a barristers' clerk. He began writing plays, but found it impossible to persuade the managers of Melbourne theatres to accept or even to read them.