He was the son of marquis John Jacob and Joanna of Savoy. He succeeded his brother William VIII who had got involved in the War of Ferrara. When the conflict's eastern front settled, Boniface had to face the advance of the Dukes of Savoy. Boniface signed a treaty of non belligerence, and had his niece Bianca married to Duke Charles I of Savoy. He also conceded to the latter the title of Montferrat in case he would die without a male heir.