After sending some of his work to J. F. Archibald at the "Sydney Bulletin", he was appointed finance editor in 1903. In this role, he increased importance of the "Wild Cat" column, a financial and investment news and insights column focused on mining companies, which eventually (by 1923) grew into "Wild Cat Monthly". Prior was promoted to associate editor in 1912. In 1914, Archibald sold his shares in "The Bulletin" to Prior, making Prior the majority shareholder. In 1915, he became the senior editor, in which position he built "The Bulletin"s reputation for literature and for financial journalism. In 1927, he was sold the remaining shares in "The Bulletin" and thus became not only its editor but its sole owner and manager. In 1928, he inaugurated the first "Bulletin" Novel Competition, offering aspiring writers prize money and the publishing of their work in "The Bulletin".