In WWII he fought with Italy as a wagoner but deserted and fled to join the resistance in Bohemia. During this time he becomes a communist, pro-Soviet, and Stalinist, directing a radio program for a while before being forced underground during the Cold War and publishing science-fiction novels under the pseudonym Omega Jim. He published many more books, all widely popular and translated in 60 countries, including Russia, Japan, and China. In the 70s and early 80s until his death, he was the editor of many magazines, including Pi Kappa, a "fantarchaeologia" magazine covering the same topics that Kolosimo did in his books. He wrote a few books in his later life with his wife, Caterina.