Sorely Boy was born in 1505, it is not known exactly where but the general consensus is that it was at  Dunaneanie Castle (Ballycastle) or Dunluce Castle. He died at the age of 85 at Dunaneanie Castle,, a remarkable age for those times and his body was interred in Bonamargie Friary.

Sorley came from a large family and had five brothers James, Colla, Angus, Alexander, Donal and several sisters. He belonged to the Scottish clan of the MacDonnells - an ancestor had married with Margaret Bisset who was heiress to a large portion of  land  along the North Antrim coast and  in the Glynns (Glens).  James the eldest son inherited the title of 'Lord of Dunyveg and Antrim Glynns' but decided to return to his native Scottish Isles accompanied by his wife Agnus Campbell , he left Colla to rule the Glynns in his absence. Colla married Evelyn MacQuillan which brought a tentative peace between the previous opposing clan, he had two sons, Gillaspick and Randal, Gillaspick died  engaging in a bull fighting at games in Ballycastle which were to celebrate his coming of age (probably at the Lammas Fair).

In 1551, the MacDonnells ruled supreme over the Route and Glynns of Antrim, so much so that the government saw them as a political threat and attempted to halt their expansion and power base by arresting Sorley Boy and placing him in Dublin Castle. James Croft was then sent with four ships to take Rathlin Island and capture Colla MacDonnell but the tables turned on their plans and Colla captured two high ranking members of the expedition, he held them to ransom for the release of Sorley from Dublin Castle.