In his early childhood, the Irwin family moved to Clayville, New York, a farming and mining center south of Utica.

A hotel business there failed too, and the family moved back to Leadville in a bungalow at 125 West Twelfth Street.

For the San Francisco-based Bohemian Club, he wrote the Grove Play The Hamadryads, A Masque of Apollo in One Act' in 1904.

As a new reporter on The Sun, he was assigned to work the Bellevue Hospital morgue, where the more than 1,000 bodies of the victims of fire and drowning were taken.

[1][8] Irwin's biggest story and the feat that made his reputation as a journalist was his absentee coverage for The Sun, in New York City, of the San Francisco earthquake of April 18, 1906.

Back on the Pacific coast in 1906–1907 to research a story on anti-Japanese racism, Irwin returned to San Francisco and found it flourishing.

"[18] During and after the war Irwin wrote 17 more books, including Christ or Mars?, an anti-war treatise (1923); a biography of Herbert Hoover (1928); a history of Paramount Pictures and its founder, Adolph Zukor, The House That Shadows Built (1928); and his own autobiography, The Making of a Reporter (1942).