Owen served as Edmund Campion's servant and was arrested for protesting Campion's innocence. Upon his release, he entered the service of Henry Garnet, a Jesuit, around 1588. For the next 18 years, Owen built hiding places for priests in the homes of Catholic families. He frequently traveled from one house to another under the name of "Little John" and accepted only the necessities of life as payment before he started off for a new project. He also used the aliases "Little Michael", "Andrewes" and "Draper". During the daytime, he would work as a travelling carpenter to deflect suspicion.