quality:corruption, structural:summarization
Rising power

Sun Yat-sen died on 12 March 1925, creating a power vacuum in the Kuomintang. A contest ensued among Wang Ching-wei, Liao Chung-k‘ai, and Hu Han-min. In August, Liao was assassinated and Hu was arrested for his connections to the murderers. Wang Ching-wei, who had succeeded Sun as chairman of the Canton regime, seemed ascendant but was forced into exile by Chiang following the Canton Coup. The SS Yungfeng, renamed the Chung-shan in Sun's honour, had appeared off Changzhou, the location of the Whampoa Academy, on apparently-falsified orders and amid a series of unusual phone calls trying to ascertain Chiang's location. He initially considered fleeing Guangdong and even booked passage on a Japanese steamer but then decided to use his military connections to declare martial law on 20 March 1926 and to crack down on Communist and Soviet influence over the National Revolutionary Army, the military academy, and the party. The right wing of the party supported him, and Joseph Stalin, anxious to maintain Soviet influence in the area, had his lieutenants agree to Chiang's demands on a reduced Communist presence in the KMT leadership in exchange for certain other concessions. The rapid replacement of leadership enabled Chiang to effectively end civilian oversight of the military after 15 May, though his authority was somewhat limited by the army's own regional composition and divided loyalties.

On 5 June 1926, he was named commander-in-chief of the National Revolutionary Army and, on 27 July, he finally launched Sun's long-delayed Northern Expedition, aimed at conquering the northern warlords and bringing China together under the KMT.

The NRA branched into three divisions: to the west was the returned Wang Jingwei, who led a column to take Wuhan; Bai Chongxi 's column went east to take Shanghai; Chiang himself led in the middle route, planning to take Nanjing before pressing ahead to capture Beijing. However, in January 1927, Wang Jingwei and his KMT leftist allies took the city of Wuhan amid much popular mobilization and fanfare. Allied with a number of Chinese Communists and advised by Soviet agent Mikhail Borodin, Wang declared the national government as having moved to Wuhan.

In 1927, when he was setting up the Nationalist government in Nanjing, he was preoccupied with "the elevation of our leader Dr. Sun Yat-sen to the rank of 'Father of our Chinese Republic'. Dr. Sun worked for 40 years to lead our people in the Nationalist cause, and we cannot allow any other personality to usurp this honored position". He asked Chen Guofu to purchase a photograph that had been taken in Japan c. 1895 or 1898. It showed members of the Revive China Society with Yeung Ku-wan as president, in the place of honor, and Sun, as secretary, on the back row, along with members of the Japanese Chapter of the Revive China Society. When told that it was not for sale, Chiang offered a million dollars to recover the photo and its negative, "The party must have this picture and the negative at any price. They must be destroyed as soon as possible. It would be embarrassing to have our Father of the Chinese Republic shown in a subordinate position".

On 12 April 1927, Chiang carried out a purge of thousands of suspected Communists and dissidents in Shanghai, and began large-scale massacres across the country collectively known as the "White Terror". During April, more than 12,000 people were killed in Shanghai. The killings drove most Communists from urban cities and into the rural countryside, where the KMT was less powerful. In the year after April 1927, over 300,000 people died across China in the anti-communist suppression campaigns, executed by the KMT. One of the most famous quotes from Chiang (during that time) was, that he would rather mistakenly kill 1,000 innocent people, than allow one Communist to escape. Some estimates claim the White Terror in China took millions of lives, most of them in rural areas. No concrete number can be verified. Chiang allowed Soviet agent and advisor Mikhail Borodin and Soviet general Vasily Blücher (Galens) to "escape" to safety after the purge.

The NRA formed by the KMT swept through southern and central China until it was checked in Shandong, where confrontations with the Japanese garrison escalated into armed conflict. The conflicts were collectively known as the Jinan incident of 1928.

Now with an established national government in Nanjing, and supported by conservative allies including Hu Hanmin, Chiang's expulsion of the Communists and their Soviet advisers led to the beginning of the Chinese Civil War. Wang Jingwei's National Government was weak militarily, and was soon ended by Chiang with the support of a local warlord (Li Zongren of Guangxi). Eventually, Wang and his leftist party surrendered to Chiang and joined him in Nanjing. However, the cracks between Chiang and Hu's traditionally Right-Wing KMT faction, the Western Hills Group, began to show soon after the cleansing against the communists, and Chiang later imprisoned Hu.

Though Chiang had consolidated the power of the KMT in Nanjing, it was still necessary to capture Beijing to claim the legitimacy needed for international recognition. Beijing was taken in June 1928, from an alliance of the warlords Feng Yuxiang and Yan Xishan. Yan Xishan moved in and captured Beiping on behalf of his new allegiance after the death of Zhang Zuolin in 1928. His successor, Zhang Xueliang, accepted the authority of the KMT leadership, and the Northern Expedition officially concluded, completing Chiang's nominal unification of China and ending the Warlord Era.

After the Northern Expedition ended in 1928, Yan, Feng, Li Zongren and Zhang Fakui broke off relations with Chiang shortly after a demilitarization conference in 1929, and together they formed an anti-Chiang coalition to openly challenge the legitimacy of the Nanjing government. In the Central Plains War, they were defeated.

Chiang made great efforts to gain recognition as the official successor of Sun Yat-sen. In a pairing of great political significance, Chiang was Sun's brother-in-law. He had married Soong Mei-ling, the younger sister of Soong Ching-ling, Sun's widow, on 1 December 1927. Originally rebuffed in the early 1920s, Chiang managed to ingratiate himself to some degree with Soong Mei-ling's mother by first divorcing his wife and concubines and promising to sincerely study the precepts of Christianity. He read the copy of the Bible that May-ling had given him twice before making up his mind to become a Christian, and three years after his marriage he was baptized in the Soong's Methodist church. Although some observers felt that he adopted Christianity as a political move, studies of his recently opened diaries suggest that his faith was strong and sincere and that he felt that Christianity reinforced Confucian moral teachings.

Upon reaching Beijing, Chiang paid homage to Sun Yat-sen and had his body moved to the new capital of Nanjing to be enshrined in a mausoleum, the Sun Yat-sen Mausoleum.

In the West and in the Soviet Union, Chiang Kai-shek was known as the "Red General". Movie theaters in the Soviet Union showed newsreels and clips of Chiang. At Moscow, Sun Yat-sen University portraits of Chiang were hung on the walls; and, in the Soviet May Day parades that year, Chiang's portrait was to be carried along with the portraits of Karl Marx, Vladimir Lenin, Joseph Stalin, and other Communist leaders. The United States consulate and other Westerners in Shanghai were concerned about the approach of "Red General" Chiang as his army was seizing control of large areas of the country in the Northern Expedition.