Since, childhood "Denny", as he is better known, was born on May 13th 1939, the same year Batman was created. O'Neil grew up in a Catholic house in St. Louis, Missouri. As a young boy he would go with his dad or granddad to the grocery store and pick up the occasional comic book. School and the Military Dennis graduated with a degree in English Lit. from the St. Louis University.
From there he joined the Navy during the Cuban Missile Crisis. Once he left the Navy he began writing for a newspaper which attracted the attention of Roy Thomas, who suggested to Stan Lee, that O'Neil take the writing test--which consisted of 4 pages to a Fantastic Four storyline. Denny took the test and Stan Lee was impressed and offered him a job. Career Once he started working for Marvel O'Neil even got to write in a story for Stan Lee when he went on vacation for a Daredevil issue.
DC and Character Creations
Dennis wrote a Batman comic book where a little girl dies because of a mine and Batman wasn't able to save her. He wanted to make the point that they should close the mines, but it failed to pass. He is primarily known for his work as a writer during the 70's. O'Neil was also one of the first writers to truly investigate the psychology of Batman. He has come to a very interesting conclusion stating that Bruce Wayne is the secret identity, the alias, while Batman is the true identity. Interestingly enough "investigating the psychology of Batman" is also what must have lead Denny O'Neil to creating the famous location in Gotham City known as Arkham Asylum which has also inspired countless video games, graphic novels, and origin stories.
He is also the co-creator to the Green Lantern John Stewart (alongside artist Neal Adams). Denny O'Neil also created the "eco terrorist" and assassin known as Ra's Al Ghul (the name when translated from Arabic means "the Demon's Head"), a man who has lived for hundreds of years, leader of the "demon's head", an organization of the world's most lethal killers, and unarguably one of Batman's most versatile enemies who also knows Bruce Wayne is his true identity. He is also the creator of Talia Al Ghul, who is infatuated with Batman (and they end up having a son, Damian Wayne)! In turn he is also responsible for the League of Assassins (which was once run by Ra's). Co-creator of the DC character Azrael alongside Joe Quesada (former Editor in Chief of Marvel Comics)
Denny is currently on the board of directors for the charity, The Hero's Initiative. His name is featured in the back of almost every DC comic book from the 70's through 2010. His work at DC comics has lasted well over 40 years.
Characters Created by Dennis O' Neil