Maria was only child of Isabella of Jerusalem and Conrad of Montferrat. She was born after her father’s death and her mother’s subsequent remarriage to Henri of Champagne. Isabella was actually visibly pregnant at the wedding. Maria herself was born at the end of both the Third Crusade and Guy of Luisignan’s attempts to remain King of Jerusalem. The city itself had long since been lost and the crusaders were unable to get it back. As a result Maria probably spent much of her childhood in the cities of Tyre and Acre.
Isabella died in 1205 and since Maria’s only half-brother, the four-year-old Amalric, Isabella’s son by Amalric II, had died earlier that same year, Maria was crowned Queen of Jerusalem at age thirteen. Her uncle, John of Ibelin, Isabella’s half-brother and son of Maria Komnene and Balian of Ibelin, ruled as regent until she turned seventeen.
Once she came of age, the issue of Maria’s marriage became a major political issue, as it had been for her mother and her aunt Sibylla. She soon married the French nobleman John of Brienne at the suggestion of the king of France Philip Augustus. The couple would only rule together for three years, maintaining a policy of peace with the neighboring Muslim sultanates. In 1212 Maria gave birth to their only child, a daughter, Isabella II of Jerusalem, also known as Yolande. The child survived. Maria did not, dying a few days after the birth and leaving her infant daughter as the next Queen of Jerusalem.