He was a younger son of William Comyn of Kilbride and Euphemia de Clavering.
He fought with his cousins the Earl of Buchan and the Lord of Badenoch at the Battle of Dunbar on 27 April 1296, where he was captured and became a prisoner of King Edward I of England until 1297 at Nottingham Castle.
He led a Scottish army with Simon Fraser crossing into England on 18 June 1303 to lay waste the countryside around Carlisle.
[1] He was forfeited of his lands in Fakenham Apes, Suffolk, England; however, he regained them after his submission to Edward I.
Edmund died fighting on the English side during the Battle of Bannockburn on 23–24 June 1314.