Horace Elmo's entry into the comic book industry is unclear. He may have begun publishing work as an amateur in the early 1920s, before obtaining a professional job producing newspaper cartoons for the New York Evening Graphic. During this time he produced many popular syndicated comics, such as Facts You Never Knew, It's Amazing, and Useless Eustace. As part of his syndication efforts he ran Lincoln Features, and later Elmo Features Syndicate, which syndicated his own work as well as comics by other creators, including Jack Kirby.Beginning around the early 1940s and into the 1950s he produced fillers for various comic book companies, notably for both National and Timely. Beginning in the mid-1950s he had several books published by Ace Books. He continued to produce syndicated newspaper comics until at least the 1970s.
Born Arazio Theodore Elmo to Italian immigrants in New York City, Elmo was the sixth of seven children, and was raised in and around Manhattan and Brooklyn. He held several different jobs before entering the comic book industry. He married Martha (née Oliver) in 1928; the cause of the dissolution of their marriage is unknown, but he later remarried to Vilma (née Molnar) in New York in 1931. They had at least two children, a daughter and a son. He passed away in the Bronx in October of 1992.