In or around 617, Feng became a trusted advisor to the chancellor Yu Shiji. As Yu was unfamiliar with civil service, Feng effectively handled the civil service matters, and the edicts that he drafted were calculated to please Emperor Yang; he would also block the submissions made by officials who had different opinions than Emperor Yang. He was harsh in his application of laws, and often reduced rewards to officials with contributions. He was therefore blamed by the "Old Book of Tang" for Emperor Yang's increasing favors for Yu and the deteriorating state of Sui governance.