Li was an early agent of
Zhou Enlai, via the Communist intelligence agency, "
Teke". Along with fellow agents
Qian Zhuangfei and
Hu Di, Zhou often referred to Li as one of "the three most distinguished intelligence workers of the Party". Under Zhou's direction Li joined the
KMT secret police as a mole by the end of 1929. Li was soon placed in charge of investigating Communist activities, and was provided with carefully selected information about the activities of parties hostile to the KMT. The information provided to Li was carefully controlled by Zhou Enlai. Li also reported to Zhou on the plans of
Chiang Kai-shek. Beginning in 1929, under the direct order of
Zhou Enlai, Li Kenong used a fake name, Li Zetian, when working inside the KMT in Shanghai. Li's work inside the KMT specialized in radio communications and cryptography. Li excelled in his work and was promoted to the section head at Shanghai. Throughout his career as a Communist mole Li took pains to pass all information of interest to the Communists. On April 25, 1931,
Qian Zhuangfei, another one of Zhou's agents planted in the
Nationalist intelligence agency headquartered at
Nanjing, who was directly under Li's control, saw the message from Wuhan announcing Gu's capture. Qian held the message from distribution while he sent his son-in-law from
Nanjing to notify Li in Shanghai. Li immediately attempted to inform CCP leaders of Gu's capture, but was not able to contact the officer in charge of CCP intelligence,
Chen Geng. Li decided to break protocol instructing agents not to contact their liaisons outside of established times. Li went to look for Chen in numerous places and eventually found him, reporting the capture of Gu. Li and Chen informed
Zhou Enlai, who arranged an emergency evacuation of as many CCP members as possible from their hiding places in Shanghai. Hundreds of Zhou's agents were thus saved, but not all. Li's open attempts to contact Gu and Zhou destroyed his "cover", and marked the end of Li Kenong's ability to serve as a clandestine member of the KMT secret police. Following his work in Shanghai, Li fled to Mao Zedong's base in
Jiangxi. Li was later appointed the head of the CCP's Jiangxi Protection Branch (
Zhengzhi Baowei Fenju), executive director (
Zhixing Buzhang) of Political Protection for the Chinese Soviet, and Chief of the
Red Army Political Protection Bureau. Upon arrival in
Shaanxi at the end of the
Long March, Li became the chief of the
International Liaison Department of the Chinese Communist Party. In 1936, after the
Xi'an Incident, he was appointed as Secretary in charge of the CCP delegation based there. During the Xi'an Incident, Li served for the first time as a principal negotiator, roles that he would repeat later on in Panmunjom (1952–3) and Geneva (1954). ==Second Sino-Japanese War==