Xiao's activities during the regencies of Yang Jun (father of Emperor Wu's second wife Empress Yang Zhi), Sima Liang and Wei Guan (who were co-regents), Empress Jia Nanfeng (Emperor Hui's first wife) and Sima Lun (Prince of Zhao) were poorly documented.
He cited that Zhang Fang had forcibly moved Emperor Hui to Chang'an and aimed to bring him back to Luoyang.
His brothers and several other prominent governors such as Wang Jun and Sima Xiao all joined him, and he also began handing out new appointments to his allies without the emperor's assent.
Among the forces in the east, only the Inspector of Yu province, Liu Qiao and the self-declared Inspector of Yan province, Sima Mao sided with Sima Yong after Yue attempted to remove them from their positions in c.September, with Liu Qiao accusing the prince of overstepping his authority.
Due to the early setbacks, a general of Yue, Chen Min, received permission to go east to recruit more soldiers.
[11] In Ji province, Sima Xiao received some elite Xianbei and Wuhuan cavalry forces from Wang Jun.