He was the officer in command of the Accursed Tower at the siege of Acre in 1291, and escaped the fall of the Kingdom of Jerusalem with his brother, King Henry II.
When his brother Henry became unpopular in Cyprus, Amalric overthrew him with the aid of the Knights Templar and some of the barons, assuming the titles of "Governor and Rector" on April 26, 1306.
It quickly collapsed, but Amalric was forced to arrest a number of nobles, including Rupen of Montfort, John of Dampierre, and various members of the Ibelin family.
In April, two of the Ibelins were exiled to Armenia, and John of Dampierre was mortally wounded by a mob after attempting to communicate with King Henry.
On his death, his brother Aimery was proclaimed Governor of Nicosia, but was soon defeated and imprisoned, and Henry restored to power.