The name Rogan is an anglicized form of the Irish Gaelic name Rógan, which is believed to have originated in the 5th or 6th century CE. The name is derived from the Old Irish word róg, meaning "choice" or "famous." This suggests that the name Rogan may have been given to children with the hope that they would grow up to be distinguished or renowned individuals.

In ancient Irish mythology, Rogan was the name of a minor character who appeared in the Ulster Cycle of tales. He was mentioned as a warrior who fought alongside the legendary hero Cú Chulainn. While not a central figure, his inclusion in these stories indicates that the name was in use during the era when the myths were first recorded, likely between the 8th and 11th centuries.

One of the earliest recorded individuals with the name Rogan was Rogan mac Rothráin, an Irish king who ruled over the Uí Failge territory (modern-day County Offaly) in the 7th century. Another notable bearer of the name was Rogan of Moville (died 637 CE), an Irish monk and saint who founded the monastery of Moville in County Down.

In the 12th century, Rogan was the name of a Scottish clergyman who served as the Bishop of Ross from 1161 to 1162. During the same period, a man named Rogan of Howth (died 1188) was a prominent Anglo-Norman landowner and military leader in Ireland.

Fast-forwarding to the 17th century, Rogan O'Muldoon (1611-1685) was an Irish soldier who fought in the Confederate Wars and later served as a colonel in the Spanish army. In the 18th century, Rogan Magranill (1703-1779) was a Scottish-Irish architect and artist who designed several notable buildings in Dublin.

These are just a few examples of the historical figures who have borne the name Rogan over the centuries. While not as common as some other Irish names, it has a long and distinguished history, with roots stretching back to the early medieval period and the ancient myths and legends of Ireland.