O'Toole is a patronymic variation of the Irish surname Toole, which is an Anglicized version of the Gaelic name O Tuathail , which means "descendant of Tuathal" which was an old Celtic name meaning "people, tribe" + "rule." Other variations are O'Tuale, O'Toughill, Toughill, Touhill, O'Twohill, Toohill, Tohill, Tohall, Toal , and Toale.

The O'Toole family is a Celtic stock and belong to the Ui Muireadhaigh clan who trace their descent back to the Cahir Mor, King of Leinster, in the 2nd Century A.D. In Gaelic the name is O'Tuathail. Tuathal in Irish means people-mighty, and O'Tuathal means the descendant of Tuathal, the name of the son of Ughaire, King of Leinster who died in 956 A.D. His descendants adopted the surname O'Tuathail, which is anglicized regularly as O'TOOLE, TOOLE, TOAL, TOHILL, etc.

In pre-Norman times they shared, with other septs of the Ui Muireadhaigh people, extensive lands in Southern Kildare. Under pressure from the Norman's they retired in the 12th century eastward to the mountain fastness of Wicklow comprising the ancient diocese of Glendalough, lands which, with their kinsmen, the O'Byrnes, they defended with unremitting resistance from the 12th to the 17th century.

The O'Toole chieftains through the years had the right of nominating the abbots of the famous monastery founded by St. Kevin at Glendalough. Because of their nearness to Dublin, the seat of English power, and because they were surrounded by the powerful Norman barons of the Pale, the maintenance of their rights entailed almost incessant warfare down to the time of the Stuart Wars when they finally lost most of their ancestral property in the confiscation's which followed the infamous Treaty of Limerick.

Stalwart courage and loyalty to their traditions may be said to characterize the family throughout the ages. Even their most illustrious representative, the great St. Laurence O'Toole, (1132-1182) Archbishop of Dublin, did not hesitate to take up arms against the Norman invaders. St. Laurence is the patron saint of the Archdiocese of Dublin. He was canonized in 1225 by Pope Honorius.

Courage and Loyalty were traits that marked the careers of a long litany of O'Toole soldiers who served as officers in the Irish Brigade throughout the 18th century in France and other European countries. Among these we may single out Captain Lucius O'Toole. He was especially chosen to take part in the dramatic adventure, which procured the rescue of Princess Maria Clementine Sobieski from Innsbruck in 1719 prior to her marriage to James III. Captain O'Toole was later killed in the battle of the Moselle.

 Most of the ancestors of the O'Toole family were Roman Catholic and their names are found on the old church records of Goshenhoppen and Conewago, Pennsylvania. The Mission of Goshenhoppen in Washington Township, Berks Co., was founded in 1741 by Father Theodore Schneider and was the first Catholic settlement outside of Philadelphia. The Conewago Mission in Heidelberg Township, York (now Adams) County was the next to be established.

The following poem records the circumstances of the loss at sea of Richard O'Toole (Richard Toole in the poem). This has been handed down by word of mouth until it was written down by Judge Margaret Spellacy, granddaughter of Marcella (O'Toole) Kelly.

On the twentieth of November, those heroes did assembled,
And left the Greystones on the sea.
They hopefully did sail, with sweet and pleasant gale,
Until to Howth's harbor they came.
Between Howth and malhide, where the seas did swell with pride
And tremendously they chafed and foamed.
Old Boris blew a squall, which overset their yawl,
And four heroes of them here met with their doom.
Brave Edward Doyle was as hardy as steel,
When the boat overturned he mounted her keel.
When four of his comrade's death's arrow did feel
He lay between hope and despair.
The Carlin, full crew, had just come into view
And heard poor Ed Doyle for to cry,
Oh, Merciful Lord, will you to me afford,
Or send some relief from on high?
Three grand attacks were then made by the crew,
But, still cruel boris wildly blew,
Their sails were all rent, and they could not pull true,
Which grieved the young heroes full sore.
When he saw each tackle losing ground,
He suddenly gave vent to his grief, saying,
Are you going away, brave boys, or can you afford no relief?
Since there is none, dear parents and friends, adieu,
This night and forever, I am lost to you.
Keen death shot its arrow, and did him subdue,
And Neptune bore off with the prize.

It was ten months before, on their own native shore,
They were very near meeting their doom,
Till John Doyle, their friend, and some more gallant men,
Saved them from a watery doom.
But, where was he? Or, was he at sea,
Or any stout hero from Wicklow to Bray?
Oh, health to you, John Doyle, wherever you be.
If he were there that night, no danger would daunt him, I'm sure.
It is now my intention, their names for to mention,
In sorrow I now must begin.
There were Joe and Edward Doyle, two brothers stout and loyal,
John Tierney and brave Michael Quinn,
Brave Richard Toole, whose loss we may deplore,
He is gone with the angels, his soul to adore.
He is gone forever to return no more
Until the Judgement of Great Counting Day.

Richard O'Toole married Esther (Essie) Lott. Their children were,

It is believed that Thomas O'Toole emigrated from Ireland at the age of fifteen, which would have brought him to this country about 1832. Thomas was a man of a large stature with red hair and a red beard down to his waist. It is believed that he came directly to the Emmitsburg area and worked at Mount Saint Mary's College all his adult life. He built a house on a plot of ground sold to him by the College and raised his family there. He married Ann Catherine Shorb (dau. of John and Magdalena (Kreitzer) Shorb) 26 Sep 1871 at St. Anthony's (old church on the hill), Emmitsburg, MD. Their children were,

Thomas and Ann, as well as the Shorbs, are buried in the Mountain Cemetery behind Mount Saint Mary's College.