After acquiring an elementary military training in Yunnan, General Li was sent to Japan among the sixth group of Chinese military students to study in the Japanese Military Cadets Academy. The course he took was in the infantry and he graduated from that institution.
After his return to China General Li became Director of the Military Lecture Hall of Yunnan and later was concurrently Councillor of the General Staff Office of the Yunnan forces. Upon the outbreak of the First Revolution in October 1911, General Li organized a Revolutionary Force with the students of the Military Lecture Hall and declared the independence of Yunnan. He was elected Vice Tutuh or Assistant Military Director.
In 1913 General Li was elected a Member of the House of Representatives of the First National Parliament which was dissolved by Yuan Shih-kai in January 1914. In 1915 he joined the Yunnan Rebellion. During Yuan Shih-kai’s monarchical movement, General Li secretly travelled between Japan, Hong Kong ana the South Sea Islands as representative of the Revolutionary forces. In March 1916 he took part in the organization of the headquarters of the Southern Expeditionary forces at the boundary between Kuangtung and Kuangsi. In July 1916 following the death of Yuan Shih-kai General Li wras appointed Civil Governor of Shenxi to succeed General Ch’en Shu- fan who had been hitherto acting in the capacity of Military Governor of that province. In October 1916 he was conferred the Third Order of Merit. In July 1917 he resigned from the Civil Governorship of Shensi owing to difference of opinion with General Ch’en Shu-fan. He was first taken prisoner by General Ch’en and afterwards he affected his escape to Peking.
During 1918 and 1919 General Li was connected with the Military government of the South in which General Tsen Chun-hsuan played a leading role. General Li has always been known as the clever advisor and right hand man of General Tsen. Thus he has been a prominent figure of the Chen Hsueh Hui, a political party, of which General Tsen was the leader.
In June 1922 after the Chihli-Fengtien War when General Li Yuan-hung re-assumed the presidency, General Li Keng-yuan was a member of the parliament which reassembled in August 1922. In September 1922 he was appointed Director General of the Government Aeronautic Bureau. In October he was awarded the Second Class Wenfu and Yun-Wei Chiangchun, a member of the College of Marshals. In November 1922 General Li was appointed Acting Minister of Agriculture and Commerce. In January 1923 he was appointed Minister of Agriculture and Commerce, of which post he was relieved in September 1923.