James Lawrence Ryan III was born to Captain James Ryan II on Caprica three decades before the Fall of the 12 Colonies of Kobol. He grew up floating from post to post as his father climbed the ranks of the Colonial Fleet.

At the age of 18 he entered the Caprica Fleet Academy. He studied there for four years before graduating as an ensign. He was then assigned to the Battlestar Valkyrie where he met then-lieutenant Johnathan Turner. The two became fast friends and wound up serving together in many assignments over the next fifteen years.

He was promoted to Colonel and selected as executive officer of the newly commissioned Battlestar Prometheus after serving as the CAG under Commander Helena Cain and her X.O., his old friend John Turner, on the Pegasus. At the time of his promotion he was one of the youngest colonel's in the colonial fleet, a fact many attributed to his his father's influence. The truth, however, was that his father, Admiral Ryan, had long before fallen out with his son.

Ryan served with distinction as the Prometheus' X.O. but was captured, along with the ship, when Alliance forces ambushed them.