Pan Jun was born in Hanshou County (), Wuling Commandery (), which is located northeast of present-day Changde, Hunan,(潘濬字承明，武陵漢壽人也。) Sanguozhi vol. 61. towards the end of the Eastern Han dynasty. After he reached adulthood around the age of 20, he studied under the tutelage of the scholar Song Zhong (宋忠; also known as Song Zhongzi 宋仲子).(弱冠從宋仲子受學。) Sanguozhi vol. 61. He was known for being intelligent, observant, and capable of providing well-thought and well-reasoned responses to questions. Wang Can, one of the "Seven Scholars of Jian'an", once said that Pan Jun was an extraordinary talent. After receiving such high praise from a famous intellectual like Wang Can, Pan Jun became more well known in his home commandery. The Administrator of Wuling Commandery appointed him as an Officer of Merit () to serve in the commandery office.(吳書曰：濬為人聦察，對問有機理，山陽王粲見而貴異之。由是知名，為郡功曹。) Wu Shu annotation in Sanguozhi vol. 61.
