Parmenion was the son of a Macedonian nobleman Philotas. During the reign of Philip II Parmenion obtained a great victory over the Illyrians in 356 BC; he was one of the Macedonian delegates appointed to conclude peace with Athens in 346 BC, and was sent with an army to uphold Macedonian influence in Euboea in 342 BC.
In 336 BC he was sent, with an army of 10,000 men, with Amyntas and Attalus to make preparations for the reduction of Asia. After Alexander was recognized as king in Macedonia Parmenion himself became Alexander's second in command of army.
After the conquest of Drangiana, Alexander was informed that Philotas, son of Parmenion, was involved in a conspiracy against his life. Philotas was condemned by the army and put to death. Alexander, thinking it dangerous to allow the father to live, sent orders to Media for the assassination of Parmenion. There was no proof that Parmenion was in any way implicated in the conspiracy, but he was not even afforded the opportunity of defending himself.