Axe is the son of Samuel D. Jericho and his wife Melanie. He was born in the West Coast Blue shortly after the two pirates were apprehended by a Marine Captain called Zolaro. Instead of taking them to Justice, Zolaro protected them and gave them a new home on his island, called Aran Island. As a boy, he came across an odd fruit that was stuffed into a old oak tree near his village. Hungry as he was, he ate it without a second thought, and continued even though it tasted horrible. Soon after devouring the foul fruit, he discovered he gained superhuman strength and that his body could be hardened to stop even bullets, but not all the time. He had eaten the Kachi Kachi no Mi, Model: Diamond.
As he grew up, he trained his body and defended his village from invaders. However, the villagers didn't think it was right for him to stay at his home forever, so they encouraged him to go out and find ancient treasures and myths. Axe knew he couldn't handle things all on his own, especially on the open ocean, so he gathered a crew and became a pirate. Sadly, after many failed expeditions, his crew mutinied against him.
So, without a crew, and a large bounty on his head, he makes his way around the world, looking for a new crew to stand by him as he fulfills his dream and plans to take revenge on those who turned on him. What those traitors didn't know was that he was trained by a man named Rayo Verrani, a man who was on his own quest for revenge. Rayo taught him how to fight in hand to hand combat, further increasing his skill and strength.
While Rayo was indeed strong by his own Fruit and way of fighting, Axe was able to stand against just about anything Rayo threw at him as they trained. During his training, Rayo taught him Rokushiki, a discipline made up of "The Six Powers". Rokushiki, while indeed powerful in each way, is incredibly tiresome on the body of a novice. Axe has yet to fully master any of the moves, but has a fondness of using the Tekkai along with his Devil Fruit Power.
After getting a couple of crewmates, Axe and his old nakama traveled to the Baratie, a floating restaurant owned and run by Chef Zeff, a former pirate called Red Leg Zeff. While there, he met with a young chef named Sanji. Axe stayed for awhile and helped out when other chefs were unable to serve, and began a friendship with both Sanji and Zeff. Axe's relationship with them granted him some lessons in the martial arts that both Sanji and Zeff knew well, as well as considering Sanji to be like a brother to him and Zeff as an uncle.
Throughout his journey with his new crew, Axe has seen, learned and done many things. One of the things he remembers most about his life, was before the new crew. After washing up on the beach of an island after being mutinied against, Axe met a young man who called himself Wraith, who turned out to be a Revolutionary. Axe traveled with Wraith for a few years, learning the trade of a Revolutionary and became close of joining the organization, but due to him finding out the truth behind his name and the legacy of his family's name, Axe rejected him and decided to take his vengeance on the World Government.
Due to his secrecy, he constantly writes in his private journal, which he keeps safe in a locked drawer in a desk in his quarters. His true name was revealed shortly after his crew and the Straw Hat Pirates invaded Enies Lobby, the Judiciary Island of the World Government.