Simon was born in Washington, D.C., the son of Dorothy Simon (nee Ligeti), a homemaker, and Bernard Simon, a former journalist and then public relations director for B'nai B'rith for 20 years. In March 1977, when Simon was still in high school, Simon's father was one of a group of over 140 people held hostage (and later released) in Washington, D.C. by former national secretary of the Nation of Islam Hamaas Abdul Khaalis in the Hanafi Siege. Simon was raised in a Jewish family with roots that originated in Eastern Europe and Hungary (his maternal grandfather had changed his surname from "Leibowitz" to "Ligeti"). He has a brother, Gary Simon, and a sister, Linda Evans, who died in 1990.

Upon leaving college, Simon worked as a police reporter at The Baltimore Sun from 1982 to 1995. He spent most of his career covering the crime beat. A colleague has said that Simon loved journalism and felt it was "God's work". Simon says that he was initially altruistic and was inspired to enter journalism by the Washington Post's coverage of Watergate but became increasingly pragmatic as he gained experience. Later in his career he aimed to tell the best possible story without "cheating it".  Simon was a union captain when the writing staff went on strike in 1987 over benefit cuts. He remained angry after the strike ended and began to feel uncomfortable in the writing room. He searched for a reason to justify a leave of absence and settled on the idea of writing a novel. "I got out of journalism because some sons of bitches bought my newspaper and it stopped being fun," says Simon.  In an interview in Reason in 2004, Simon said that since leaving the newspaper business he has become more cynical about the power of journalism. "One of the sad things about contemporary journalism is that it actually matters very little. The world now is almost inured to the power of journalism. The best journalism would manage to outrage people. And people are less and less inclined to outrage," said Simon. "I've become increasingly cynical about the ability of daily journalism to effect any kind of meaningful change. I was pretty dubious about it when I was a journalist, but now I think it's remarkably ineffectual." In 1988, disillusioned, Simon took a year's leave to go into the Baltimore Police Department Homicide Unit to write a book.

What was his relationship with journalism?
Simon worked as a police reporter at The Baltimore Sun from 1982 to 1995. He spent most of his career covering the crime beat. A colleague has said that