Feng, like many young officers, was involved in revolutionary activity and was nearly executed for treason. He later joined Yuan Shikai's Beiyang Army and converted to Christianity in 1914. Feng's career as a warlord began soon after the collapse of the Yuan Shikai government in 1916. Feng, however, distinguished himself from other regional militarists by governing his domains with a mixture of paternalistic Christian socialism and military discipline (he was reputed to have liked baptizing his troops with water from a fire hose), thus earning the nickname the 'Christian General'. In the early 1920s, Feng rose to prominence in the Zhili clique of warlords, named so because their base of power was centred around Zhili. This Zhili Clique defeated the Fengtian clique, headed by Zhang Zuolin, father of Zhang Xueliang, in the First Zhili-Fengtian War. It was at this time that Feng also began to move closer to the Soviet Union.
In the Second Zhili-Fengtian War of 1924, organizing the Guominjun, Feng Yuxiang along with Hu Jingyi and Sun Yue betrayed his fellow warlords, an act that contributed to the weakening of the Zhili Clique and would later open the door for the Northern Expedition. It also gave Zhang Zuolin control of Beijing. During the Northern Expedition, Feng shifted loyalties again, this time supporting Chiang Kai-shek to the detriment of Zhang Zuolin, who was forced to evacuate North China. By 1929 Feng's Guominjun clique controlled most of north-central China, but because he was under increasing pressure from the expanding power of the Nanjing government, he and Yan Xishan launched the Central Plains War against Chiang Kai-shek but were defeated by forces loyal to Nanjing.
Stripped of his military power, Feng spent the early 1930s criticizing Chiang's failure to resist Japanese aggression. On May 26, 1933, Feng Yuxiang became commander-in-chief of the "Chahar People's Anti-Japanese Army Alliance", with Ji Hongchang as frontline commanderActions in Inner Mongolia (1933-36)#Anti-Japanese Allied Army 1933. With a strength claimed by Feng to be over 100,000 men, Ji Hongchang's army pushed against Duolun, and by July 1933, drove the Japanese and Manchukuoan troops out of Chahar Province.
By late July, Feng Yuxiang and Ji Hongchang established, at Kalgan, the "Committee for Recovering the four provinces of the Northeast". Chiang Kai-shek, fearing that communists had taken control of the Anti-Japanese Allied Army, launched a concerted siege of the army with 60,000 men. Surrounded by Chiang Kai-shek and the Japanese, Feng Yuxiang resigned his post, while Ji Hongchang fought on for a while before seeking asylum in Tianjin in January 1934.
Between 1935 and 1945, however, Feng Yuxiang supported the KMT and held various positions in the Nationalist army and government. From 1935 to 1938 he was the Vice-President of the National Military Council and a member until 1945. After the Second Sino-Japanese War began in 1937 he was Commander in Chief of the 6th War Area.
After World War II, he traveled to the United States where he was an outspoken critic of the Truman administration’s support for the Chiang regime. He died in a shipboard fire on the Black Sea en route to the Soviet Union in 1948 and his remains were buried with honors in China in 1953.