|Family||John Oak (Father), Daniel Oak (Son), Lester Oak (Son)|
Gregory was the only son of John Oak, a farmer on Ollieland. Gregory got married to an unknown wife around 142 BBU. It was around this time in Ollieland that the third great war broke out. Gregory's wife was pregnant with his son, Lester Oak , and Gregory decided to move somewhere safer. Gregory moved to Pallet Town in Theoland along with his wife. His son was born 2 months later in 139 BBU. Gregory later had another son, Daniel. Gregory died of a fever in 100 BBU.