During Murong Chui's reign, Murong De served as a chief official and general, and Murong Chui often listened to his advice. For the first several years of Later Yan's existence, he often carried out campaigns to secure areas that were being held by semi-independent warlords. In particular, around the new year 387, he, assisted by his nephew Murong Long, was successful in defeating the Jin vassal Wen Xiang (溫詳) and the Jin rebel Zhang Yuan (張願), taking the territory near the Yellow River.