As head of the oldest line of the descendants of Iestyn ap Gwrgan, he claimed supremacy over the neighbouring Welsh lords of Meisgyn and Glynrhondda.
[2] In the fight against Gilbert de Clare, who was the heir of Isabella and thus in 1217 came into the possession of Newcastle as Lord of Glamorgan, he was supported by his relative Morgan ab Owain from Glynrhondda, who attacked Margam Abbey in 1224.
Nevertheless, he could not enforce his claims, but he received increasing support from Prince Llywelyn the Great of Gwynedd, who wanted to expand his influence in Glamorgan.
[4] In 1233 he supported together with Llywelyn the Great a failed revolt of Richard Marshal, 3rd Earl of Pembroke against the English King Henry III.
[5] Morgan Gam was married twice, first to Janes ferch Elidyr Ddu and second to Ellen, daughter of Gronw ap Einion.