As Arrhidaeus grew older it became apparent that he had mild learning difficulties. In Plutarch's report, he became disabled by means of an attempt on his life by Philip II's wife, Queen Olympias - who wanted to eliminate a possible rival to her son Alexander - through the employment of pharmaka (drugs/spells); however, this claim is considered by most modern authorities as unlikely to be true.

Alexander was fond of him and took him on his campaigns, both to protect his life and to ensure he would not be used as a pawn in a challenge for the throne.

After Alexander's death in Babylon, Arrhidaeus was proclaimed king by the Macedonian army in Asia; however, he was a mere figurehead, and a pawn of the powerful generals, one after the other. The crater Ariadaeus on the Moon is named after him.