Monda was born in Velletri (Metropolitan City of Rome Capital) into a family of liberal Catholic politicians, and currently remains a practicing Catholic himself. His father, who died of a heart attack when Monda was 15, was mayor of Cisterna di Latina, a city south to Rome, and helped finance films, including some by the Taviani brothers, who employed the young Monda in 1981. His brother Andrea, currently editor of L’Osservatore Romano is also a writer, and has published several books on Tolkien, C. S. Lewis and Chesterton. His daughter, Marilù, published the fantasy saga "L'eredità dell'ombra".