John Constantine was born in Liverpool, England. His identical twin died in the womb and his mother died giving birth to John, who then grew up with a neglectful and abusive father. Constantine began practicing magic and performed his first spell as a child, which was to dispel himself of his childhood innocence. When he became an adult, Constantine moved to London where he spent time as a rock star, before a failed exorcism inspired him to become a private investigator and vigilante specialising in magic and the occult. He was once romantically involved with fellow magician Zatanna, was an infrequent ally of Swamp Thing and was a founding member of Justice League Dark. Constantine is the keeper of the House of Mystery.
Constantine is an expert in various forms of magic, from subtler tricks that allow him to manipulate his enemies and create his own luck, to more elaborate spells which allow him to harness pyrokinesis, necromancy, illusions and even teleportation. Constantine is also resistant to telepathy and mind control, and is a capable hand-to-hand combatant. A blood transfusion from the demon Nergal is believed to have mildly enhanced his healing and slowed his aging.
He is frequently seen wearing a brown jacket along with a red tie and a white shirt. His hair is blonde. Constantine was originally created to resemble rock musician Sting. When he appears 10-years-old in "Trick or Threat", he is seen constantly with a rock candy stick in his mouth in a veiled reference to the character's chain-smoking habit from the comic books.