Because his father had consecutively sired two children with his mother, Juno, the Roman form of Hera, was made Jason's guardian to placate the indignant goddess, as Jupiter went so far as to name his newborn son after his wife's favorite hero, Jason, in the attempt to appease his wife for his infidelity.
When Jason was young, Juno commanded his mother to bring him to the Wolf House.
Jason also receives a prophecy saying that he must beware the earth, possibly because Gaea, the Earth, is his enemy and that she bears arms to the Doors of Death.
It was then that he was separated from his mother and sister to be initiated by Lupa in the ways of Rome.
After training for some time under the she-wolf, he journeyed to Camp Jupiter where he was raised in the lifestyle of the Roman Legion.
Eventually, Jason was inducted into the Fifth Cohort and would begin restoring a sense of honor to the disgraced contingent. While the Greeks were fighting Kronos and the main Titan army in the Battle of Manhattan, Jason and Reyna led the Twelfth Legion in an assault on Mount Othrys where he fought through an army of Scythian dracanae and defeated the Titan Krios himself.
When he was a centurion of the Fifth Cohort, his cohort would get jobs such as clearing out the basilisks from under Temple Hill. His actions, which resulted in the destruction of Mount Othrys, led the members of the legion to raise him to the rank of praetor.
When an unnaturally powerful storm arrives, Dylan revealed himself to be a ventus or venti, a storm spirit (Greek form: anemoi), and Jason instinctively took out his gold coin, flipped it, and it became a well balanced sword made of Imperial Gold.
While he and Piper fought off Dylan, Hedge (who revealed himself to be a middle aged satyr) climbed down the canyon wall to retrieve Leo when he was thrown down.
Jason then meets Chiron who immediately realizes who Jason is by speaking in Latin, to which he responds in Latin.
Afterwards they find out Hera is in danger, and Jason must lead a quest in order to save her.
Few details are known about the quests Jason went on during his days at Camp Jupiter, however some of his accomplishments include leading a quest to find and slay the Trojan sea monster, which included him staying at Aeolus's palace for a few days, doing a favour for the god Bacchus involving a missing leopard in Sonoma, and going on a quest with Reyna to Charleston to retrieve a stash of Imperial Gold torpedoes from the C. Jason wakes up on a bus belonging to the Wilderness School holding hands with a girl he doesn't even know.
He finds that he has no memory of even going to the school or having a best friend named Leo and a girlfriend named Piper.
Jason reveals his godly parent through the summoning of a lightning bolt, showing that he is a son of Jupiter.