Jin Xuan was a descendant of Jin Midi, and he was from Jingzhao (present-day Luoyang, Henan). He took up several appointments in the Han Dynasty imperial court, including Gentleman of the Yellow Gate (黃門侍郎), Consultant (議郎), General of the Household (中郎將), before becoming Administrator (太守) of Wuling Commandery.
After the Battle of Red Cliffs in 208, the warlord Liu Bei set off to attack the four commanderies in southern Jing Province, namely Changsha, Guiyang, Lingling and Wuling. Jin Xuan was killed in battle against Liu Bei's forces and Wuling became part of Liu's territory.
Jin Xuan appears in chapter 53 of Luo Guanzhong's historical novel Romance of the Three Kingdoms as the Administrator of Wuling. At that time, Liu Bei sent his general Zhang Fei to attack Wuling. Jin Xuan wanted to resist the invaders but his Assistant Officer, Gong Zhi, advised him to surrender. The following day, Jin Xuan fought with Zhang Fei outside the city but was defeated and forced to retreat. However, he was betrayed by Gong Zhi, who killed him with an arrow shot to the face. Gong Zhi later surrendered Wuling to Zhang Fei.