Zheng Xi was a kinsman and younger contemporary of Koxinga who became the figurehead of the brief succession dispute that followed the warlord's death in 1662. He grew up within the Zheng commercial-military house and held subordinate commands during the years when Koxinga's forces operated out of southern Fujian. He accompanied the great crossing to Taiwan in 1661–1662, settling in the new Tungning territory with the bulk of the senior generals. When Koxinga died suddenly in Tainan in June 1662, the heir presumptive — Koxinga's eldest son Zheng Jing — was still stationed at Xiamen and was viewed by some on Taiwan as compromised by a notorious sexual scandal. A faction of senior officers led by Huang Zhao and Xiao Gongchen sought to circumvent Zheng Jing's accession and to install Zheng Xi as ruler of the new island domain. The party physically secured Zheng Xi in Tainan and issued proclamations in his name, presenting him as the legitimate continuation of Koxinga's mission. Zheng Jing responded by crossing the strait with his Xiamen garrison in late 1662 and routing the rival faction in a short, decisive campaign. Huang Zhao was killed and Xiao Gongchen executed, while Zheng Xi himself, having been a largely passive participant, was placed under house arrest. In the years that followed he was effectively sidelined from political life and reportedly sent back to Fujian, where he ultimately submitted to the Qing court. His later years are sparsely documented and his date of death is not reliably recorded. The episode established Zheng Jing's undisputed succession and shaped the Tungning court's lasting wariness of intra-clan rivals. Zheng Xi is remembered chiefly as the unwitting focal point of Taiwan's first dynastic crisis rather than as a ruler in his own right.

• Briefly contested the succession against Zheng Jing in 1662