Hadden got his start in newspaper writing at Brooklyn's Poly Prep Country Day School, where he wrote for the school magazine, the Poly Prep, and distributed a hand-written, underground sheet to his classmates that was called The Daily Glonk. Moving to the Hotchkiss School, Hadden wrote for the Hotchkiss Record, a weekly newspaper. After an intense competition, Hadden was elected the chairman of the newspaper and Luce the assistant managing editor. Hadden then turned the Record from a weekly into a bi-weekly.
At Yale, Hadden was elected to the staff of the Yale Daily News and later served as the paper's chairman twice (1917-1918 and 1919-1920). Luce was the News' managing editor the second time. While at Yale, Hadden was a brother of Delta Kappa Epsilon (Phi chapter) and a member of Skull and Bones.:150 It was during a break from school, when Hadden and Luce traveled south to Camp Jackson, South Carolina as ROTC officer candidates, that they began seriously discussing the idea of creating a magazine that would condense all the news of the week into a brief and easily readable "digest."
After receiving his bachelor's degree from Yale in 1920, Hadden wrote for the New York World, where he was mentored by one of New York's most famous and accomplished newspaper editors, Herbert Bayard Swope. In late 1921, Hadden wrote to Luce, who had recently been let go by the Chicago Daily News, and suggested that they both go to work for the Baltimore News. In Baltimore, they spent their nights working on the idea of a news magazine, which, at first, they planned to call Facts.
In 1923, Hadden and Luce co-founded Time magazine along with Robert Livingston Johnson and another Yale classmate. Hadden and Luce served alternating years as the company's president, but Hadden was the editor for four and a half of the magazine's first six years, and was considered the "presiding genius." Johnson served as the magazine's vice president and advertising director. In its earliest years the magazine was edited in an abandoned beer brewery, subsequently moving to Cleveland in 1925, and returning to New York in 1927. For the next year and several months, both Time and The New Yorker were edited at 25 W. 45th Street in Manhattan. Thus the two greatest magazine editors of the 1920s — Briton Hadden and Harold Ross — worked in the same building.
In December 1928, Hadden became ill. He died two months later, most likely of streptococcus viridans, which had entered his bloodstream, causing septicemia and ultimately the failure of his heart. Before he died, Hadden signed a will, which left all of his stock in Time Inc. to his mother and forbade his family from selling those shares for 49 years. Within a year of Hadden's death, Luce formed a syndicate, which succeeded in gaining hold of Hadden's stock.