Jango started his life as a farmer on the planet Concord Dawn, a planet known for the Mandalorian presence there. Mandalorians were an ancient nomadic group of warriors that often found work as bounty hunters, soldiers for hire, and mercenaries. During a Mandalorian civil war, Jango's family was killed and he was taken in by Mando leader Jaster Mereel. Over the years, Jango worked his way up to become one of Jaster's most trusted and gifted lieutenants. When Jaster was betrayed by his second in command, the sole survivor was Jango, and he along returned to Mando planet of Mandalore to replace Jaster as the leader of the Mandalorians. Jango remained the Mandalore (the title given the Mando leader) until the Mandelorians were all but wiped out in a battle with a group of Jedi lead by Jedi Master Dooku. Jango Fett was, again, the only survivor, though he was captured by the Jedi and turned over to the local government on the planet were the battle took place. The governor there sold Jango into slavery, but he later escaped and went on to become a bounty hunter. He later acquired the ship Slave I which would go on to become famous under his son, Boba.
Shortly after the Trade Federation invaded the planet Naboo (during the events of The Phantom Menace), Jango was contacted by a man named Tyrannus about tracking down a former Jedi turned crime lord (who turned out to be one of Dooku's former apprentices). With the completion of that mission, Tyrannus (who would later be revealed as Dooku himself, now a Sith) offered Jango another job, to be the genetic template for an army of clones, the best ever assembled. Jango agreed, even though it meant leaving behind everything he knew. He went to the planet Kamino, where the cloning was taking place. He also trained several groups of the clone soldiers before his death at the hands of Mace Windu during the Battle of Geonosis. As part of his payment, he was also given one of the clones, minus the accelerated aging and downloaded tactical data - essentially an ordinary Mandalorian baby - who he named Boba and adopted as his son. He began training Boba at a very young age in the craft of bounty hunting, and turned him into a fierce survivor, the only reason Boba was able to survive on his own after his father's death.
After being confronted by Obi-Wan Kenobi on Kamino, Jango fled the planet and met up again with Dooku on the planet Geonosis with his son. There, the Jedi Obi-Wan Kenobi and Anakin Skywalker had been captured, along with the Senator Padme Amidala. The large group of Jedi came to rescue the Jedi and confront Dooku and the army he seemed to be assembling. On Geonosis, Fett's clones got their first combat experience led by Jedi Master Yoda. Jango, however, died during the battle and his son Boba disappeared. Boba Fett returned some 20 years later piloting Jango's ship, the Slave I and becoming a bounty hunter himself.