He dominated court politics following Emperor Zhenzong's death, by associating with the powerful grand councilor Ding Wei.
In May 1019, he sent Lei Yungong to the sacred Mount Mao in Jiangning Prefecture to cast his "jade tablet with a golden dragon".
In May 1021, he was made director of Zhao Zhen's residential palace in charge of his household, as well as supervisor of the school for imperial princes.
In November 1021, he was further promoted, along with his subordinate Liu Congyuan (劉從愿), to become Palace Courier (內殿承制), the same position Zhou Huaizheng held before his death.
Lei then lied to Liu Congyuan about the edict, claiming all it stated was to honor his aunt—and thus monopolized power in the imperial palace.