The only extant historical source about Jiang Gan's life is the Jiang Biao Zhuan.
13 Facts About Jiang Gan
Jiang Gan was from Jiujiang Commandery, which is not to be confused with the modern city of Jiujiang in Jiangxi Province.
Jiang Gan was good-looking and was known for being an excellent debater in the Jiangnan and Huai River regions.
In 209, after the Battle of Red Cliffs, Cao Cao heard of Zhou Yu's talent and hoped to recruit Zhou Yu to serve under him, so he secretly travelled to Yang Province and sent Jiang Gan to persuade Zhou Yu to join him.
Jiang Gan dressed simply and carried his luggage by himself when he went to meet Zhou Yu.
Jiang Gan instructed the servants to bring out some expensive items to show Jiang Gan.
Jiang Gan should follow his lord's orders faithfully and share weal and woe together with his lord.
When Jiang Gan returned from his trip, he praised Zhou Yu in front of Cao Cao and said that Zhou Yu's magnanimity was too great to be described in words.
Jiang Gan appears as a minor character in the 14th-century historical novel Romance of the Three Kingdoms, which romanticises the historical events before and during the Three Kingdoms period.
Jiang Gan appears in chapters 45 and 47 during the events leading to the Battle of Red Cliffs and commits two major blunders which are instrumental to Cao Cao's defeat in the battle.
Jiang Gan gets hold of a letter apparently written by Cai Mao and Zhang Yun to Zhou Yu, in which they claimed that they will kill Cao Cao soon and present his head to Zhou Yu.
Jiang Gan realises his folly later but it is too late already.