Ripley went to the Academy with the intent to become a science officer, but was sidetracked by his newfound love for the classics. His father was an engineer and his mother a renowned mathematician. He was a disappointment to their legacy, achieving average grades as well as being unlucky in love. While visiting them at Starbase 31, the Jem'Hadar attacked. Both his parents were killed by them, but he managed to hide in a jefferies tube. The feeling of helplessness he experienced inspired him to change his focus to security at the Academy. Because of his change in focus and his continuing love for the classics, he stayed an extra year.
His first assignment was aboard the ill-fated USS Farragut E. After its destruction he became Chief of Security aboard the USS Bonaventure.