During the succession struggle after the death of Duke Xian of Jin 晉獻公 (r. 677-651), Xi Cheng was a follower of Prince Yiwu 夷吾 and not of Prince Chong'er 重耳. Together with Xi Rui 郤芮 and Lü Sheng 呂省, he bribed the duke of Qin 秦, at whose court Prince Yiwu lived in exile. Duke Mu of Qin 秦穆公 (r. 659-621) in fact escorted Prince Yiwu back to Jin, where he was enthroned as Duke Hui of Jin 晉惠公 (r. 651-637).
Fourteen years later, when Duke Hui died and the throne fell to Prince Chong'er, Xi Cheng feared being punished as a partisan of Prince Yiwu and therefore planned to rebel at the side of Xi Rui against Duke Wen 晉文公 (r. 637-628, i. e. Prince Chong'er). Yet the plot was revealed, the Duke escaped and had his opponents eliminated with the support of the Duke of Qin.