He lived in a small village, population 200, above a cliff in Italy. Angelo lost his virginity to another boy from his village, but did so in the forest to keep things secret. He also went to a schoolmaster every day to learn English so that he might go to America for change, something he sought.
When going through customs at Ellis Island, Angelo tried to steal Jack Harkness' visa and was subsequently arrested. Jack visited Angelo in his cell, and used his Time Agency wrist strap to change the name on his visa to Angelo's, preventing him from being deported. Upon reaching New York City itself, Jack and Angelo then rented a room together, where they began a physical relationship.
The two began to distribute "sacramental wine", during a period of prohibition, but were kidnapped almost immediately by the local mob. After suggesting that they work for the mob, they were given the job of moving a crate from one warehouse to another. Despite being told to flee, Angelo persuaded Jack to let him stay, and the two set about their task. When they arrived at the warehouse, Jack admitted that he was on a mission from Torchwood, and opened the crate to reveal a brain parasite that the Trickster's Brigade were planning to use on the future US President Franklin D. Roosevelt in an attempt to disrupt the flow of history by allowing Nazi Germany to win the Second World War. When the parasite tried to attack Angelo, Jack killed it and dissolved its corpse, completing the mission, but was shot in the head when trying to escape, while Angelo was arrested.
Upon his release from prison a year later, Angelo was surprised to find that Jack was alive and waiting for him. Despite rejoining him, Angelo assumed that Jack must be the Devil, and stabbed him. He was shocked when Jack came back to life again, and showed this to some people at a butcher's shop where a crowd of people soon gathered. The crowd repeatedly killed him to witness the resurrection despite Jack's screams of pain, some possibly gathering vials of his blood. When the crowd left, Angelo freed Jack and planned to go with him. However, Jack no longer trusted Angelo, and jumped off of a building in a symbolic gesture and to prevent Angelo from following him. (TV: Immortal Sins)
Angelo researched how to become immortal like Jack, and by using more conventional means than Jack had, managed to remain alive until 2011. With information from Jack, Angelo navigated the 20th century well enough to become considerably wealthy. The Three Families who decided to attempt to recreate Jack's immortality chose not to include Angelo because he had had a relationship with another man. He later married a woman, and had at least one child and a granddaughter. After his initial encounter with Jack, he followed his life, and kept pictures of him in his house. Angelo spoke openly of their relationship. (TV: End of the Road) When the Torchwood Hub was destroyed (TV: Children of Earth: Day One), Angelo successfully acquired some of its alien technology including the null field generator from the ruins. Though he knew of the Families' actions and the Miracle, he did not know exactly how they achieved it. (TV: End of the Road)
After the Miracle began, Angelo enlisted his granddaughter Olivia to keep Jack safe, so she captured Gwen Cooper's family, and told her to bring her Jack. (TV: The Middle Men, TV: Immortal Sins) Gwen, Jack and the rest of the Torchwood team were taken to Angelo's house. Jack spoke to Angelo despite the fact that he was unconscious. Jack removed Angelo's respirator, to kiss him, assuming that Angelo could not die anyway due to the Miracle. Angelo then became the first person to die since Miracle Day because of the null field that was underneath his bed, cancelling the effects of Miracle Day at that one spot. (TV: End of the Road)