In contrast to most of the National Revolutionary Army, it was controlled by the Chinese Communist Party and not by the ruling Kuomintang.

The New Fourth Army was established on December 25, 1937 in Hankou, moving to Nanchang on January 6, 1938, when the detachments began marching to the battlefront.

At the beginning, the New Fourth Army had four detachments and one task force battalion and numbered roughly ten thousand.

The army was fully reorganised after the incident and remained in active combat until the end of the war.

After the Japanese had occupied Wuhan the New Fourth Army took the opportunity to set up several guerrilla camps in the area.

In order to establish a new base area the New Fourth Army sent an advance team to Northern Jiangsu and clashed with guerrillas of the Nationalist forces there.

The Chinese Communist Party (CCP) made a strong protest and announced the rebuilding the New Fourth Army in northern Jiangsu.

Due to a lack of troops the Japanese ceased actively attacking the New Fourth Army.

The New Fourth Army tried to establish base areas in eastern Zhejiang, Hunan and Hubei Province.

However, in middle Jiangsu Su Yu's 1st Division miraculously won despite having fewer forces and wiped out 56,000 Nationalist soldiers.

With the rapid expansion of the size of the army a large number of junior officers and newly recruited students needed training.

In the first three years of its existence the New Fourth Army operated independently with the regiment as its basic unit.