Alauddin's reign was marked by increased conflict with his Portuguese and their Malay and Sumatran allies and his dispatching of envoys to the Ottoman sultan, Suleiman the Magnificent in the 1560s.

The queen mother had great influence in the state and appointed a regent called Raja Bungsu who had a green payung (parasol), a symbol of authority, and a house opposite the royal abode.

Being dissatisfied with conditions in the capital, he staged a royal coup in c. 1537 or 1539, killed Raja Bungsu, and imprisoned Salahuddin and the Queen Mother Sitt Hur,[1] who would die years later in 1548 and 1554 respectively.

Thus he was supposedly the ruler who divided Acehnese society into administrative lineage groups (kaum or sukeë), but it is unclear whether this attribution is correct.

The Portuguese traveler Fernão Mendes Pinto mentions that the sultan asked the king of the Bataks to convert to Islam, and attacked him when he refused.

In order to strengthen his case, Alauddin dispatched envoys to the Ottoman sultan, Suleiman the Magnificent, around 1561–1562, asking for assistance against the infidel Portuguese.

An alternative route for pepper trade therefore developed from about 1530, where Gujarati, Arab, Turkish and Acehnese traders brought spices directly from Aceh to the Red Sea without coming near Portuguese strongholds in the Melaka Straits.

This campaign was apparently coordinated with the attack on Portuguese Goa by the Deccan Sultanates of Bijapur, Golconda, Bidar and Ahmadnagar.

The superior artillery and more robust ships of the Portuguese explain part of the repeated Acehnese failures, which Turkish help could not make up for.

Although Sultan Alauddin was not actually militarily successful against Portuguese Melaka, his reign witnessed the beginning of the high tide of Aceh's power.