Born to Christoffer Davion and the grandson of the famous Jackson Davion, Julian grew up hearing the stories of his family's honor. Just like his family before him, he entered into the military and learned his skills at the New Avalon Military Academy. Julian was easily able to enter the exchange program which got him to be transferred to The Nagelring.
While attending at The Nagelring, he fell in with Callandre Kell who had a history of being unrestrained. Julian would find himself being expelled from the school and exiled from the Lyran Commonwealth at the command of the Archon. The stain on his honor left a black mark for years even though the First Prince Harrison Davion was able to smooth the situation out.
Julian was never close to Caleb Davion, his cousin and heir of the Federated Suns; their relationship was even more strained when Harrison appointed Julian as Prince's Champion, the youngest ever. As the Champion, he spent most of his time troubleshooting problems throughout the Suns' realm and staving of incursions by the Taurian Concordat. His ability with dealing with situations grabbed the attention of Duchess Amanda Hasek, who worried some due to her independent streak but did not worry Harrison due to his belief in Julian's undying loyalty.
In 3134, Julian Davion accompanied First Prince Harrison Davion to Terra for the funeral of Victor Steiner-Davion. There he was ordered by the Prince to assist The Republic with his honorary command of the 1st Davion Guard with brewing conflict with the Rogue Senate. At the various gatherings on Terra, he meets many of the young nobles from the various Inner Sphere powers. After a dispute between Caleb and Yori Kurita, the prince's son names Julian as his champion in Trial of Refusal using Republic's simulators to re-fight the War of 3039 as single battle. He fights Yori Kurita to a draw.
After the death of Prince Harrison Davion, Caleb Davion is announced as the First Prince of the Federated Suns. Julian, who Caleb thought was trying to steal the throne for himself, is dismissed as Prince's Champion and is relegated back to the role as commander of the 1st Davion Guards. The 1st Davion Guards, under Julian's command, continue with the last order of Prince Harrison which is to bring stability to The Republic.
He and his coalition force were sent by the Exarch to Ronel in 3135 in an attempt to stop Conner Rhys-Monroe and his Alliance forces from capturing the planet with its functional HPG Station. He fought a number of grueling battles against the Alliance forces. It was not until after the collapse of the Republic that this coalition force was able to defeat Conner. Julian allowed Conner and his Alliance force to ransom some of their equipment and withdrew from Ronel in good faith. Gavin Marik-Davion then approached Julian, and offered his services as a spy and provided him with the gift of information, including evidence that Caleb Davion is insane and Prince Harrison had died on Terra.
As the coalition broke up and returned homes, Julian decided to remain on Ronel to uphold the orders of the Exarch to defend the planet. Callandre Kell elects to remain with Julian to watch his back.
Julian and the Guards stayed within Republic space long after the walls came up, fighting to protect the worlds that they once controlled. Eventually, the Federated Suns military sent them to help defend Tharkad against the attacks by both Clan Jade Falcon and Clan Wolf. Once the news of Caleb's death and his own election by the Federated Suns Privy Council as the new First Prince reached him, he reluctantly took up the crown of the Federation.
|First Prince of the Federated Suns
| Succeeded by|
- He holds the title of Lord Markeson.
- He has honorary commander of First Davion Guards, which includes Fortress-class Dropship, Markeson's Pride.
- He is the youngest person to hold the title of Prince's Champion.
- He is a MechWarrior and pilots Templar Assault Mech.
- Era Report: 3145, p. 92, "Julian Davion profile"
- Sword of Sedition, pg. 6
- Sword of Sedition, pg. 126