Chan Chak, courtesy name Choushuo, unofficial English name "Andrew", was born in Wenchang, Guangdong Province (now Hainan Special Administrative Region), China. His family moved to Singapore when he was three years old, and returned to China at the age of eight.
Upon completion of elementary school, he enrolled in the Guangdong Navy Academy in the city of Guangzhou; it was during this time he joined the Tongmenghui which sought to overthrow the Qing Dynasty.
After the fall of Qing and the establishment of the Republic of China, he participated in the failed opposition against Yuan Shikai, and fled to Hong Kong.
In 1917, at the start of the Constitutional Protection Movement, he supported Sun Yat-Sen. Then in June of 1922, he coordinated in the extraction of Sun when Sun clashed with political rival Chen Yuming.
In 1923, he was made the commanding officer of the Guangdong Fleet. After the 1926-1928 Northern Expedition, the Guangdong Fleet was renamed the 4th Fleet, and he remained its commanding officer.
Throughout the Warlord Era he participated in several naval engagements in Southern China.
At the beginning of the Second Sino-Japanese War Chan was given the additional position of Commander of the Fortresses of Humen; during a battle there in 1938 his left leg was wounded which eventually necessitated its amputation.
In 1939 Chan, then a Rear Admiral, was sent to Hong Kong as Liaison Officer of the Nationalist Government. Under the cover as a stockbroker, he arranged for the transportation of material into China despite the Japanese blockade, and at the same time liaised with British colonial authorities, keeping the local Chinese population on-side, controlling the Triad gangs and identifying Japanese sympathisers.