William Baker was the son of Floyd Baker and his wife. William's father left while William was an infant. As a child, impoverished, he learned how to steal. Young William loved going to the beach and building sand castles, but trips to the beach were far and few between because his mother was an alcoholic. One day William built a large and detailed sand castle only to watch it wash away when it started to rain. The young Baker boy became determined that he was going to make something that would last. William took his love of making things out of sand and used it for school art projects.
The events that led up to William Baker becoming the Sandman vary from account to account. In one telling, Flint caught Vic and Marcy having an affair. After beating up Vic, he went on a crime spree that led to yet another incarceration. Sent to Ryker's Island, Flint eventually broke out of prison, causing the manhunt that led to him getting his powers. Another states that during one of his later arrests, Flint learned that his father was released from prison and broke out in order to be with him.
It was during his flight from the authorities that Flint Marko was exposed the radiation that gave him his powers. Accounts of the actual cause vary. Originally, it was stated that Flint hid from the authorities at the site where a nuclear bomb was being tested. Another account states that Marko was near the site of a nuclear reactor that detonated, and yet another states that he hid in a cave where radioactive waste was being stored. Whatever the case, after being exposed to radiation, his body interacted with the sand under his feet mutating Marko in such a way that he could turn his body into sand and manipulate each grain to shape any form he desired. Flint has stated that it was after his powers he caught Vic and Marcy together and unleashed his powers on them in a fury before fleeing, but he left them alive.
