The name Donnell is derived from the Gaelic personal name Domhnall, which is composed of the elements domhnu, meaning "world," and val, meaning "ruler" or "prince." It originated in Ireland and Scotland, where it was a popular name among the Gaelic dynasties.

Domhnall was the name of several Irish kings and princes in the medieval period, including Domhnall Ua Néill, the King of Ailech and Cenél nEógain in the late 10th century, and Domhnall Mac Raghnaill, the King of Dublin in the 11th century. The name was also borne by Scottish kings, such as Domnall II, the King of Scots from 889 to 900.

The earliest recorded instances of the Anglicized spelling "Donnell" date back to the 16th century, when it was used as a variant of the Gaelic name Domhnall. Notable historical figures with this name include Donnell Balloch, a 16th-century Scottish clan chief and military leader, and Donnell O'Cahan, an Irish chieftain and leader of the O'Cahan clan in the late 16th and early 17th centuries.

Other notable individuals named Donnell throughout history include:

1. Donnell Gault (1616-1678), a Scottish soldier and military officer who fought for the Royalist cause during the English Civil War.
2. Donnell Mackey (1616-1695), an Irish Catholic priest and theologian who served as the Bishop of Cork and Cloyne.
3. Donnell Sampson (1790-1864), an Irish-born soldier who served in the British Army and fought in the Napoleonic Wars and the War of 1812.
4. Donnell Deeny (1846-1929), an Irish politician and Member of Parliament for East Mayo from 1900 to 1918.
5. Donnell Woolford (born 1967), an American former professional football player who played as a cornerback in the National Football League.

While the name Donnell has roots in Gaelic culture and history, it has been adopted and used widely across various regions and cultures over the centuries.