After Zhou Yu's death, Lu Su was appointed as Colonel of Vehement Martial Might () and succeeded Zhou Yu. He took charge of the 4,000 troops and the four counties which used to be under Zhou Yu's control. Cheng Pu succeeded Zhou Yu as the Grand Administrator () of Nan Commandery (南郡; around present-day Jingzhou, Hubei). Lu Su was at Jiangling County initially, so he moved to Lukou (陸口; in present-day Jiayu County, Hubei) and garrisoned there. Lu Su governed with justice and benevolence, and the number of troops under his command increased to over 10,000. He was subsequently promoted to Lieutenant-General () and appointed as the Administrator of Hanchang Commandery (漢昌郡; around present-day Pingjiang County, Hunan).