Warning: Spoilers follow
Dylan Hunt was born on the plant Tarn-Vedra. He is human, half genetically enhanced because his mother was a heavy-gravity worlder.
Dylan served two years as an enlisted man. He then attended the High Guard Academy and graduated with honors. He served in Argosy Special Ops and commanded the Crimson Eclipse.
Immediately prior to his command on the Andromeda, he was given a secret mission to extradite the dictator Ferrin from the planet Mobius so he could stand trial on Tarn-Vedra for war crimes. When he confronted Ferrin he was shot in the side and Ferrin was killed. The mission was still seen as a success by the High Guard and Dylan was given command of the Adromeda and his partner on the mission, Gaheris Rhade, was made his first officer.
He dated Sarah for several years and they were going to get married until Dylan was presumed dead or lost at the Battle of Hephaistos.
At the Battle of Hephaistos, Dylan was betrayed by his first officer and best man, Gaheris Rhade. His crew abandoned ship and he killed Rhade in self defense. The Andromeda was pulled near a black hole and experienced very extreme time dilation. While seconds passed for Dylan and the Andromeda, 303 years passed for the rest of the universe.
Dylan was rescued when the Eureka Maru attempted to salvage the Andromeda. He convinced the crew of the Maru to join him and help him restore the now fallen Systems Commonwealth.
Presently he has helped form a small Commonwealth, with about 50 member worlds.