There is dispute as to whether McCann comes from the Irish Mac Anna, "son of Annadh", or Mac Cana, from cana, meaning "wolf cub". At any rate, the major family of the name were known as lords of Clanbrassil, an area on the southern shores of Lough Neagh in the modern Co. Armagh, which they conquered from the O'Garveys. They appear to have been a branch of the Cenél Eoghain, the large group of families claiming descent from Eoghan, one of the sons of Niall of the Nine Hostages, the fifth century founder of the Uí Neill dynasty. The death in 1155 of one of their chiefs, Amhlaoibh Mac Cana, is recorded in the Annals of the Four Masters with praise for his chivalry, his vigour, and the fine strong drink he made from the apples in his orchard. Armagh apples are still renowned for their flavour. The last recorded Chief of the name, Donall MacCanna, was still known as lord of Clanbrassil as late as 1598.
Today, the surname is found principally in counties Armagh, Tyrone and Antrim, though it has also spread southwards into the provinces of Leinster and Connacht.
The family name is recorded in the townland of Annagh McCann's in Louth parish in Co. Louth.
.Patrick McCanna was a member of the United Irishmen in Paris during the Terror. He accompanied Wolfe Tone on his expedition to Ireland and went on to become successful merchant in Boulogne.
Tomás Mac Anna (1920 -) was artistic director of the Abbey theatre for many years. His son, Ferdia Mac Anna is well-known as a novelist, particularly for The Last of the High Kings (1992), despite an earlier incarnation as Rocky De Valera, leader of the proto-punk Rocky De Valera and the Gravediggers.
John McCann (1905-1980) was an extremely popular playwright in his day, as well as pursuing a successful career in politics. His son Donal McCann (1943 - ) has had international success as a stage and film actor.