Generalissimo Chiang Kai-shek (蔣介石 Jiang3 Jie4 Shi2), also known in short as "Gimo", was the leader of the National Party of the Republic of China, known as the Kuomintang (KMT). A disciple and brother-in-law of Sun Yat-sen, Chiang and his wife Soong May-ling were nominal Methodists, a fact that would have enormous repercussions on the US China policy during World War II and beyond in part due to publicity generated by the publisher of Time Magazine Henry Luce, himself a child of missionaries in China.
After the death of Sun Yat-Sen, Chiang was able to take control of the Guomindang by his political tactics. In 1927, Chiang led the Northern Expedition whose aim was to unify China under the control of the Guomindang.
Chiang's strategy during World War 2 opposed the strategies of both Mao Zedong and the United States. The US regarded Chiang as an important ally able to help shorten the war by engaging the Japanese occupiers in China. Chiang, in contrast, used powerful associates such as H. H. Kung in Hong Kong to build the ROC army for certain conflict with the communist forces after the end of WW2. This fact was not understood well in the US. The US liason officer, General Joseph Stilwell, eventually deduced that Chiang was going to let the US save him from fighting Japan, but was not able to influence US policy. (As a side note, Stilwell's frustration is apparent in his diaries. He refers to Chiang as "peanut head" on a regular basis.)