Aldous was an accountant for a major Earth corporation. He enjoyed his job, living in a world of numbers, and had a wife, Sarah, and two daughters. At some point, they took a vacation to Mars. While in a crawler, about half way across Amazonis Planitia, the ground gave way beneath them. Aldous awoke in the hospital to find that his entire family had perished in the accident. He grieved for a long time, finally going back to work only to find that it no longer appealed to him at all.
Taking leave, Aldous encountered a man bearing a staff who claimed to be the last of his kind – the last seeker of the Holy Grail. He told Aldous he felt he was a man of infinite goodness and potential. When he lay dying, he passed his staff along to Aldous, who left his old life behind to seek the Grail himself.
In 2258, he arrived at Babylon 5 to meet with the Ambassadors of each race to see if they had any idea where the Holy Grail may be located. He was met by Cmdr. Jeffrey Sinclair and a full honor guard, at the request of Ambassador Delenn, who was in awe of Gajic (the Minbari have great respect for all seekers). Neither the Minbari nor the Centauri (and presumptively not the Narn) had any information about the Grail.
While aboard, he also met a man named Thomas "Jinxo" Jordan, a good man who had been caught up in some unfortunate circumstances. Aldous agreed to rehabilitate Jordan when he was arrested. Aldous offered a contrasting view to Jinxo's belief that he was a walking 'Babylon Curse' and claimed he should be called "Lucky" for narrowly avoiding disaster so many times. He also saw a potential in Jinxo due to his willingness to keep the station safe by staying, risking his livelihood. Jinxo soon had an underworld boss named Deuce come after him for a debt. Aldous was briefly able to hold off Deuce's minions using staff fighting techniques he had learned.
Aldous was later captured however and discovered Deuce had a Na'ka'leen Feeder, and was feeding it victims consciousness and memories to it as a way of destroying those who would testify against him. Aldous prevented the feeder from killing Ombuds Wellington, but was shot and fatally injured by Deuce in a crossfire with station security. Upon his death, Jinxo took up his staff and continued the quest. Aldous claimed during his dying moment that he could see the Grail.
- "Grail" episode writer Christy Marx named the character Aldous Gajic after Mira Furlan's husband, Goran Gajic.