After Sun Jian's death in 191, Han Dang continued serving under Sun Jian's eldest son, Sun Ce. He accompanied Sun Ce on his conquests in the Jiangdong (or Wu) region. The captured territories later served as the foundation of the state of Eastern Wu. Han Dang was promoted to Colonel Who is First to Ascend () and given 2,000 troops under his command and 50 horses. In 200, Han Dang pledged allegiance to Sun Ce's younger brother, Sun Quan, after Sun Ce was assassinated in a hunting expedition. He participated in the battle against a minor warlord Liu Xun, the Battle of Jiangxia, and the campaign at Poyang (). He was later appointed as the Chief () of Le'an County (樂安縣; northeast of present-day Dexing, Jiangxi). The Shanyue – tribal peoples in the Wu territories – were afraid of him and submitted to his administration.