In 1853, he was called to assist Zeng Guofan in joining the Xiang Army to suppress the Taiping Rebellion in their native province of Hunan.

During the suppression of the Taipings Rebellion, Guo distinguished himself as a prominent advocate of the local likin tax as a means of financing the campaigns.

Guo became an important member of China's Self-Strengthening Movement in the 1860s and 70s and distinguished himself for his advocacy of a moderate and peaceful foreign policy.

In 1877 the English artist Walter Goodman was commissioned to paint his portrait,[2] exhibited that year at the Royal Academy[3] and later at the Walker Art Gallery in Liverpool.

He subsequently became a great proponent of railways and other modern engineering development in China, incurring the wrath of conservative and anti-railway Court officials, who resented his representations.