He was a son of Xi Ke 郤克 and served Duke Li 晉厲公 (r. 581-573) as a minister.
In 578, war erupted with the state of Qin 秦. Xi Qi was sent to the state of Lu 魯 to ask for military support, but he did not properly transmit the wish of his ruler and was criticized by Zhongsun Mie 仲孫蔑, the chief minister of Lu.
In 575, he commanded the army of Jin in a campaign against Chu 楚 whose army he defeated in the battle of Yanling 鄢陵.
At another occasion, Xi Qi seized a tract of land owned by Yiyang Wu 夷陽五. Duke Li used this occasion to have Xu Tong 胥童 and Yiyang Wu killed his unreliable minister.