Now, that I have your attention* Gents!
Black Irish - usually means Irish Catholic people with black, raven or very dark brown hair to go along with the traditional 'see-through'- Irish skin - the Whiter Shade of Pale as it were.
My Dad is Black Irish. He tans up a storm even at 86. One time, he was chased out of Turkey Bird Saloon(Salt-water Irish,Raw Jaws, Boys from Home, F.B.I. -Foreign Born Irish) and not for being a Narrow Back ( Narra' Back -American Irish - Probably Hanley's House of Happiness, though that too would have entered into 'the equation' on 79th Street Just East of Ashland in 1947.
My Dad was given a hard time and the door, because some of the Lads thought -'What's this little Dago doing in our saloon?' The Old Man is a hard character (Pacific Campaign in the War: 1943-'45 and all) but he always deferred to the rage and the talents of the aboriginal Irish when it came time to giving a gent the boots.
He was so dark that he was taken for an Italian. The Black Irish faced hurtful moments - pain and oppression.
Movie Star Tyrone Power comes to mind as being Black Irish. Actors Gabriel Byrne and Scottish born Mick Sean Connery come to mind as well.
There are people of mixed race African and Irish blood in the West Indies and Africa.
Many historians including Thomas Babington Macaulay, 1st Baron Macaulay 1800-1859 who thought the Black Irish to be descended from Miles Hispaniae - Spanish Soldiers who are often called the roots of Black Irish Hair.
However here is a pretty good and scholarly explanation from the Site Dark Fiber.
According to rumors and legends, these Black Irish are the descendants of a few surviving ill-fated Spanish sailors who sailed with the Felícima Armada from Spain to invade England but were ultimately shipwrecked on the northern and western coasts of Ireland in the autumn of 1588. A very small number of the more than seven hundred Spanish men who made it alive to the Irish coast survived, and a few of those who did allegedly became intimate with enough Irish women so as to engender a new inter-racial (Hibernian-Iberian) strain of progeny whose "dark hair and eyes and soft brown Southern skin testifies to its remote Spanish ancestry."(4)
This story has been retold by a number of Irish and Irish-Americans of this decade by way of explaining their own "dark hair and eyes" -- although from personal experience these facial characteristics have never been matched by a "brown Southern skin." No folk or scholastic literature (to the best of my knowledge) exists to verify this Hispanic ancestry and, indeed, it is doubted whether there is any proof at all to the claims of Spanish blood in Irish veins. Without written historical authentication of these beliefs, the story has been relegated to a strictly oral tradition, bar the few variants that are cited below.
The four following variants are the sum total of referents found regarding connubial Spanish-Irish relations in reference to the Armada's descent of 1588. It should be noted that all four come from 20th century sources.
Variant one: Anyone who goes along the coast of Ireland and along the Devonshire (SW England) coast will in one locality after another find that the inhabitants of this or that village are asserted to be descendants of the men from the Armada wrecked upon their coast; that the dark complexion of the population is owing to the fact that a number of men of the Armada settled and married in that part of the district.
-- Major Martin Hume, The Geographical Journal, XXVII: 5 (London, may 1906) p 448
Variant two: A few others [i.e., Spanish survivors of the shipwrecked Armada] escaped. There were other Irish girls who pitied them and took them home and forgot that they were enemies; so that even now on that coast a child is occasionally born whose dark hair and eyes and soft brown Southern skin testifies to its remote Spanish ancestry.
-- Lorna Rea, The Spanish Armada (New York 1933) p 160
Variant three: The belief that men of Spanish appearance in County Galway [W Ireland] may be descendants of men who came ashore from the ships of the Armada and inter-married with the Irish...
-- T.P. Kilfeather, Ireland: graveyard of the Spanish Armada (Dublin 1967) p 63
Variant four: When she discovered that I was living in Spain, she -- an Irish-American -- remarked that she herself had Spanish blood in her veins. Asked to explain further, she replied that her family had always said that she was "Black Irish" to explain her dark brown hair, eyes, and personal like of Spain, and that these features were inherited from a Spanish forebear who had sailed with the Armada, been shipwrecked, and later married into her ancestral Irish family.
-- personal account of a conversation with Mary Jean Goodman,
an Irish-American born in Minnesota (St. Paul 1978)
* Red Headed Eddie Carroll - The SouthSide Roofer with Old World Quality, Standards and Work-force - said that 'He would poke at her in fun.' Damn white of you, Eddie!