 He inherited the Lordship of Beirut from Hugh of Ibelin.In 1258, by "manipulat[ing] the complex regency laws", John and his compatriot John of Jaffa, succeeded in aligning the feudatories of Jerusalem with the Republic of Venice against that of Genoa in the War of Saint Sabas.He took part in a very large raid alongside the Templars into Galilee in 1260.