Deane was born in Clontarf, a suburb of Dublin. His family lived close to the families of both Bram Stoker and Florence Balcombe (Bram Stoker's wife), and his mother had been acquainted with Bram Stoker in her youth.
Deane entered the theater as a young man, first appearing in 1899 with the Henry Irving Company (Stoker was stage manager for Henry Irving for many years). Even before he formed his own troupe in the early 1920s, Deane had been thinking about bringing Dracula to the stage. Stoker had attempted this in 1897 but the verdict from Irving consigned it to the waste-paper basket. Unable to find a scriptwriter to take on the project, Deane wrote the play himself in a four-week period of inactivity while he was suffering with a severe cold. He then contacted Florence Stoker, Bram's widow, and negotiated a deal for the dramatic rights.
Deane re-imagined Dracula as a more urbane and theatrically acceptable character who could plausibly enter London society. It was Deane's idea that the count should wear a tuxedo and stand-up collar, and a flowing cape which concealed Dracula while he slipped through a trap-door in the stage floor, giving the impression that he had disappeared. Deane also arranged to have a uniformed nurse available at performances, ready to administer smelling salts should anyone faint.
Deane’s play premiered in the Grant Theatre, Derby in June 1924. Despite critics' misgivings, the audiences loved it. With Raymond Huntley as the Count and Deane as Van Helsing, it was a huge success and toured for years. Deane had initially intended to play the role of the count himself. When the play crossed the Atlantic in 1927, the role of Dracula was taken by the then-unknown Hungarian actor Bela Lugosi. For its US debut, Dracula was rewritten by the American playwright John L. Balderston. The show ran for a year on Broadway and for two more years on tour, breaking all previous records for any show put on tour in the United States. It is the Deane/Balderston interpretation upon which the classic Tod Browning film Dracula (1931) was based.