Born in Chicago, Lloyd F. Lonergan was one of five children of Thomas Lonergan, a newspaper publisher. His mother was a writer for various newspapers, and eventually all of his siblings became newspaper writers too. Lonergan attended the US Naval Academy at Annapolis, MD. He later went to work for the William Randolph Hearst organization as a newspaper and magazine writer and worked on a number of newspapers, including the New York Evening Journal and the New York Evening World. He was eventually hired by the newly formed Thanhouser Company as a scriptwriter, and penned the company's first picture, The Actor's Children (1910). He later married Molly Homan, the sister of Thanhouser founder Edwin Thanhouser's wife. He left Thanhouser in 1915 after company executive (and his close friend) Charles J. Hite was killed in an auto accident and founder Edwin Thanhouser sold the company to an investor syndicate. Lonergan went to work for Universal Pictures as a scriptwriter. However, Thanhouser returned and bought the company back not long afterwards —the new owners had no idea how to run a film studio and were losing a fortune— and Lonergan also returned, staying for the next two years. In 1917, as the studio's fortunes declined and it was on its last legs, Lonergan left for good. He retired for a while, but came back in late 1917 to edit the serial The Million Dollar Mystery (1914) into a feature to be re-released by Arrow Film Corp. He later returned to scriptwriting also, although mostly for low-budget independents, and wrote such films as A Common Level (1920) for Transatlantic Films, Why Women Sin (1920) for Wisteria Productions and My Lady's Garter (1920) for Maurice Tourneur Productions. He died in New York City on April 6, 1937, after a long illness.