He was the eldest son of Philip I and Catherine de la Tour du Pin.
While his father had been stripped of the Principality of Achaea in 1307 by the Angevins of the Kingdom of Naples, James continued to use the princely title and even passed it on to his successors.
James had backed the young Angevin queen Joanna I of Naples when John II, Marquess of Montferrat sought to take advantage of her youth and inexperience to gain broader lands in northern Italy starting in 1344.
After the Angevin defeat at the Battle of Gamenario in 1345, John and his allies moved next to attack Chieri, a town loyal to James.
This treaty included provisions for Galeazzo II Visconti to marry Bianca of Savoy, sister of the count.