Yusof Ishak was appointed the first local head of state, the Yang di-Pertuan Negara, and took up office at the Istana.

Due to Hari Raya Puasa (Eid al Fitr) moving through the civil year as a Muslim lunar calendar date, the grounds of the Istana are sometimes open only once when two public holidays are near together.

The grounds are also often used for state functions and ceremonial occasions such as swearings-in, investitures and the presentation of credentials by heads of foreign missions.

It has a tropical layout like a Malay house, surrounded by statuesque columns, deep verandahs, louvred windows and panelled doors to promote cross-ventilation.

The building sits in its elevated position overlooking its stately grounds, the Domain, reminiscent of the great gardens of England.

The Guardian was made by Indian labourers who constructed the Istana and was presented to Sir Shenton Thomas to commemorate his taking up of residence there.

An architectural feature at top of the main building is a rectangular cupola with a flagpole which marks the highest point of the Istana complex.