Sean grew to hate the "elitist" Jovian government and blamed Zeon for his father's death. It wasn't until 5 years later that a friend told him about rumors going around about the former Federation. Everyone had believed them to have all perished after the war's end, but people had been mentioning about some survivors acting as pirates along the many trade routes between the colonies. After he graduated, he packed up all his possessions and joined up with a shipping company and signed up to go on some of the regions that had been attacked in the past.

After several months of waiting, the ship he was working on was attacked. The "pirates" were definitely from the former Federation, and he saw it as his chance to get his revenge. He snuck on board their ship in an empty storage container and waited it out until he was discovered. The Captain of the ship was so enraged to hear about the stowaway that he was ready to jettison Sean out into space until he pulled out his father's dog tags. After listening to his story, the Captain was willing to let him stay onboard.

Upon arriving at Luna II, the young man saw that his gamble had paid off. This would be the path to his revenge. The Captain had talked to some of the higher-ups and accepted him into the ranks. He served onboard several different "pirate" ships as a low ranking officer but eventually took up piloting Mobile Suits as well. Sean had been with the Old Federation for almost 10 years when the incident involving the new colony drops. He knows that the time for his revenge is near, and is ready for that chance.