Gregory Potter was born in 216 BBY, as the eldest brother of the Potter family. In 205 BBY, he received an application to Pilot Academy and he attended it to become a pilot like his father and grandfather.
Gregory Potter was optimistic, hard-working, and supportive, especially of his little brother, Ronald. He was also something of a tease, but this was only seen with Ronald and it was not above average for their relationship. He was also kind-hearted and sincere.
Five years later, Ronald would join the Jedi Temple. Gregory wrote to Ronald almost as much as his father did, and showed an extent of interest in his Jedi career. He also had a girlfriend named Enowyne, who he met at the Academy. It is likely that his experiences with her furthered his understanding of Ronald’s relationship with Annabeth Skywalker.
Gregory returned to Tatooine during Spring Break and again for the summer each year, just like Ronald did.
When Gregory Potter returned to Tatooine at the end of his fifth year at the Academy, he asked his father if they could get Ronald into Pilot School, knowing this was his dream and considering his brother could always reapply. When Ronald returned home, Ronald’s dad suggested the transfer he and Gregory had arranged, but Ronald baffled Gregory when he revealed that he had chosen to stay at the Jedi Temple. He received a letter from Annabeth and Gregory asked to see his lightsaber.
At one point, Gregory Potter went with the other students to Hoth for a two-week field trip. Gregory did not enjoy it, as he later revealed to Ronald Potter.
In the summer between 199 and 198 BBY, Gregory returned slightly before Ronald. When Ronald arrived home and stepped out of the space bus, Gregory Potter immediately threw a wet washcloth at him to suppress the heat. Ronald and Gregory were then given a ride home by their father. At one point in the summer, Ronald vented to Gregory that he could not wait to return to the Jedi Temple, where he felt people understood him. However, Gregory was confused by Ronald's wording, only rendering Ronald more distraught than before.
During the victory celebration proceeding the Battle of the Jedi Temple, Annabeth raced up to Ronald and kissed him on the lips. This surprised Ronald, who did not want to tell Gregory about it or it would be a long time before he let that go. When Ronald came home a Padawan Learner, Ronald then greeted Gregory, who figured out that Ronald and Annabeth kissed each other on the lips. When Ronald asked Gregory how he figured it out, Gregory said "a brother knows."