How did OHenry begin his career?

William Sydney Porter's (O. Henry) writing career began when he served a five-year prison sentence at the federal prison in Ohio from 1898 to 1903 for embezzlement.

While incarcerated, he began writing short stories to support himself and his daughter who lived with her Aunt Evelina (Mrs. Ashcraft) during that time. O. Henry's first published story was 'Whistling Dick's Christmas Stocking'. Although he became famous for his short stories only after his released he began his writing during this period of great personal adversity.