Born in St. Louis, Missouri and son of a medical doctor, Thomas worked a number of jobs including as a page in the 41st Congress, studying law, and gaining some practical railway work experience before he turned to journalism and became editor of the Kansas City Mirror in 1889.

Thomas had been writing since his teens when he wrote plays and even organized a small theatrical touring company.

Subsequently, he was hired to succeed Dion Boucicault adapting foreign plays for the Madison Square Theatre.

His first successful play, Alabama, was produced by Kirke La Shelle in 1891 and its financial reward allowed Thomas to write full-time.

Other plays along the same lines include Arizona (1900), In Mizzoura (1893), Colorado (1900) and Rio Grande (1916).