The great-grandson of the famed general, Gan Ning, he was involved in the suppression of Shi Bing's rebellion, but later allied himself with Chen Min in his takeover of the Jiangnan region in 305.
Gan Zhuo later became an important retainer of the Prince of Langya and future emperor Yuan of Jin, Sima Rui, participating in campaigns against Zhou Fu, Hua Yi and Du Tao to consolidate his position in the Jiangnan.
In 322, Gan Zhuo raised an army against the Jin commander, Wang Dun as he attacked Emperor Yuan at Jiankang, but his indecisiveness and old age stopped him from preventing the imperial forces' defeat, and he was soon assassinated by his subordinate.
The local gentry, led by Zhou Qi and Wang Ju (王矩), planned to overthrow Shi Bing and soon began openly raising their armies.
Later on, the Prince of Donghai, Sima Yue summoned Gan Zhuo to have him serve as an Army Advisor and appointed him as the Prefect of Lihu (離狐; southeast of present-day Dongming, Shandong).
With the imperial court distracted by civil war, Chen Min had intention of declaring independence in the Jiangnan, and Gan Zhuo agreed with his plans.
He pretended to be ill unless his daughter could be delivered to him, and once he received her, he lowered the bridge, gathered the boats on the southern bank and led the Jin forces to defeat Chen Min.
[9] In 322, the general, Wang Dun launched a rebellion and led his forces to attack Jiankang, ostensibly to remove the corrupt officials, Diao Xie and Liu Huai, who Emperor Yuan favoured.
He also contacted Sima Cheng and the Inspector of Guang province (廣州, modern Guangdong), Tao Kan, to attack Wang Dun at his base in Wuchang (武昌; present-day Ezhou, Hubei).
Halfway through his march to Wuchang, he decided to stop at Zhukou (豬口; southeast of present-day Jingshan, Hubei) and planned to rescue Sima Cheng, who was besieged by Wang Dun's general, Wei Yi (魏乂) at Changsha.
[12] Wang Dun had the officials, Zhou Yi and Dai Yuan killed, and he sent messengers with the Zouyu Banners (騶虞幡) to Gan Zhuo's army to get them to surrender.
His Commandant, Qin Kang (秦康) and Yue Daorong urged him to persist, advising him to take Pengze to cut off communications between Wang Dun's forces in Wuchang and Jiankang so that their troops will disperse.
After learning that Gan Zhuo had failed to take any precautions, Wang Dun sent a secret order to the Prefect of Xiangyang, Zhou Lü (周慮) to kill him.