During the 1920s he studied in the Soviet Union and became a key contact with the Comintern, organizing the CCP labor movement in the United Front with the Kuomintang.

When his armies were driven from the region, he joined the Long March but lost a contentious struggle for party leadership to Mao Zedong.

After his active role in the May Fourth Movement in 1919, Zhang became one of the most prominent student leaders and later joined the early organization of the CCP in October 1920.

He led several major strikes of railway and textile workers,[2] which made him a pioneer of the labor movement in China along with such figures as Liu Shaoqi and Li Lisan.

His "Li Lisan line" called for the rural soviets to launch immediate attacks on major cities, which had ended in disastrous failure.

[5] In the winter of 1930-1931, Zhang and the 28 Bolsheviks ousted Li from power and set about bringing the far-flung rural soviets under more centralized control.

[6] Xu Jishen and the other commanders wanted to seize the breadbasket counties in eastern Hubei to fix Eyuwan's chronic food shortages.

Zhang compared the plan to Li Lisan's "adventurism", and when they disobeyed his orders and took the land anyways, he got permission from the Central Committee to make Chen Changhao political commissar of the Fourth Red Army.

[7][8] Zhang and Chen accused the Fourth Red Army was acting like a "warlord-bandit" force, pillaging the countryside and rejecting proper discipline.

Slowly he turned it into a prosperous autonomous region by way of land reform and enlisting the support of locals, establishing the Northwest Chinese Soviet Federation.

The main disagreement was Zhang's insistence on moving southward to establish a new base in the region of Sichuan that was populated by ethnic minorities.

[citation needed] Zhang decided to carry out his plan on his own, with disastrous results: over 75% of his original 80,000 + troops were lost in his adventure.

Zhang lost the power and influence to be able to challenge Mao and had to accept his failure as a result of the disaster which only left him 427 surviving troops from the original 21,800.

[citation needed] In 2006, the writer and producer, Sun Shuyun, provided an account of the Long March that took exception to various ways in which the event has been propagandized.

Zhang kept the now figurehead position of Chairman of Yan'an Frontier Area and was frequently subjected to humiliation by Mao and his allies.

Zhang was too proud to ally with Wang Ming, who had recently come back from Moscow and was acting as the Comintern's representative in China.

[citation needed] But without any power, resources, and support, Zhang never held any important positions afterward and only did research on the CCP for Dai Li.

[2] Zhang was highly critical of the proceedings of the first PRC Police leader Luo Ruiqing during the Chinese Civil War.