By 1882 de Mille was employed at the Madison Square Theatre reviewing and later revising submitted plays, during which he became acquainted with the playwrights Steele MacKaye and David Belasco.

[2][3] On December 10, 1883, de Mille's first original play, John Delmer's Daughters, or Duty, opened at the Madison Square Theatre and closed a week later.

Three years later, on September 18, 1886, Main Line, or Rawson's Y, a Western melodrama written in collaboration with Charles Barnard, opened at the old Lyceum Theatre.

The play, a love story set at a remote railroad way station (complete with authentic RR tracks) and telegraph office, received warm opening night reviews.

[4] A short while later de Mille would join forces with David Belasco in a collaborative effort that would prove to have a greater box-office appeal with the theatergoing public.

[8] As he was finishing The Lost Paradise, de Mille read Henry George's famous treatise Progress and Poverty and immediately became a dedicated Georgist "single-taxer".