The name Mackenna has its origins in the Gaelic language, stemming from the combination of the prefix "mac" meaning "son of" and the name "Cionnath," which is derived from the Old Irish word "cenn" meaning "chief" or "leader." This name was prevalent among clans in Scotland and Ireland during the medieval period, particularly in the Scottish Highlands and the northern regions of Ireland.

One of the earliest recorded instances of the name Mackenna can be found in the Annals of Ulster, a chronicle of medieval Irish history, dating back to the 12th century. This historical record mentions a MacCionnaith clan, which is believed to be an early variation of the name Mackenna.

In the 16th century, a notable figure named Mackenna Og led a rebellion against the English forces in Ireland, displaying the significance of this name among Irish clans during that era. Another prominent individual named Mackenna was Sir John Mackenna, an Irish military officer who served in the Spanish Army of Flanders during the Eighty Years' War in the late 16th and early 17th centuries.

Moving forward, the name Mackenna gained recognition in the literary world with the Irish writer and playwright St. John Mackenna (1856-1919), who was known for his works on Irish culture and mythology. Additionally, Sir Joseph Nathaniel Mackenna (1903-1984) was a prominent jurist and legal scholar from South Africa.

Another notable figure was John Mackenna (1808-1888), an Irish-born journalist and newspaper editor who played a significant role in shaping public opinion during the 19th century in the United States. Furthermore, the name Mackenna has been associated with several religious figures, including Reverend Mackenna, a Catholic priest who served as a chaplain in the American Civil War during the 1860s.

Throughout history, the name Mackenna has held a strong presence, particularly in regions where Gaelic culture and traditions were deeply rooted. Its origins can be traced back to the medieval era, and it has been carried by individuals from diverse backgrounds, including military leaders, writers, jurists, and religious figures, leaving an indelible mark on various aspects of society.