The position of Colonial Secretary was subsequently created with a view to replacing Resident Councillor in Singapore.

When Singapore adopted its new constitution in 1955, although the Colonial Secretariat was abolished, the chief secretary remained an ex-officio member of the Council of Ministers and the Legislative Assembly.

[8] Nineteen people served as the Colonial Secretary of the Straits Settlements from 1867 to 1942, excluding acting officials.

On the other hand, the main duties of the Colonial Secretary was to oversee and coordinate administration, while that of the Resident Councillor of Singapore under the EIC's administration covered areas such as law enforcement, land use, vessels, postal services, custom affairs and municipal services.

[10] In July 1896, the British Government formed the Federated Malay States (FMS), which comprised Selangor, Negeri Sembilan, Perak and Pahang in the Malay Peninsula, with the Governor of the Straits Settlements concurrently as High Commissioner of the United Kingdom to Malaya.

[12] During Japan's invasion of Singapore in January 1942, the then-Colonial Secretary Stanley Jones was revoked from his position due to alleged ineffective defence coordination.

[13] The position was taken over temporarily by FMS Federal Secretary Hugh Fraser, who retreated to Singapore.

Following the unconditional surrender of Japan in 1945, the United Kingdom set up a provisional military government without restoring the post, so as to prepare for the dissolution of the Straits Settlements, in response to the post-war situation.

Its Governor restored the civil government, while Penang and Malacca, previously part of the Straits Settlements, were incorporated into the newly formed Malayan Union.

In June 1959, the State of Singapore was established according to constitutional arrangements; under British suzerainty, the Governor was replaced by the Yang di-Pertuan Negara while the position of Chief Secretary was abolished.

[16] Nevertheless, the Chief Secretary still controlled areas such as Singapore's foreign affairs, internal security, defence, broadcasting and public relations.

[16] The Council of Ministers continued to be chaired by the Governor, while the Legislative Assembly was to be presided over by the Governor-appointed Speaker; The Colonial Secretary, together with the Attorney-General and the Financial Secretary continued to remain as ex officio members in both bodies, leaving them the only members who were concurrently colonial civil servants.

[17] The Colonial Secretary had the power to issue warrants to arrest and deport any persons suspected of endangering public order and social stability.

[22] Persons who were taken into custody and deported by the Colonial Secretary included Hau Say Hoan (侯西反), an anti-Japanese Chinese businessman who resided in Singapore for 38 years.

[22] He was accused by Sir Alexander Small, the then-Colonial Secretary of being anti-British and engaging in dealings with illegal organisations to endanger public order in December 1939;[23] Small invoked the Expulsion Order and deported Hau, and prohibited him from re-entry.

[35] In addition, Colonel Ronald MacPherson, the inaugural Colonial Secretary of the Straits Settlements was the only holder to have died in office.

[36] According to data in 1892, the annual salary of the Colonial Secretary of the Straits Settlements was $10,800 (Straits dollar), the second highest among colonial officials in British Malaya after the Governor; the third highest-paying was the Resident Councillor of Penang, with a salary of $9,600 per year, excluding bonuses.