The name Sullivan has its origins in the Irish language and culture, tracing back to the medieval period. It is derived from the Old Irish words "sólámus" and "sómailus," which mean "eye" or "light of the eye." These words are thought to have been used as descriptive names or nicknames for individuals with striking or distinctive eyes.

One of the earliest recorded instances of the name Sullivan can be found in the Annals of the Four Masters, a chronicle of medieval Irish history compiled in the 17th century. The annals mention an individual named Suileabhán mac Muireadhaigh, who lived in the 12th century and was a member of the Uí Bhriain dynasty that ruled the Kingdom of Thomond (present-day County Clare).

During the Middle Ages, the name Sullivan was particularly prevalent in the southwestern regions of Ireland, especially in the counties of Cork, Kerry, and Limerick. It was associated with several influential Gaelic families, including the O'Sullivans and the MacCraith Suilleabhains, who were powerful lords and chieftains in their respective territories.

One notable figure in Irish history bearing the name Sullivan was Donal Cam O'Sullivan Beare (c. 1561-1618), a Gaelic lord and military leader who led the O'Sullivan Beare clan during the Nine Years' War against English forces in the late 16th and early 17th centuries. His legendary march from West Cork to Leitrim, known as the O'Sullivan Beare's March, is a celebrated event in Irish folklore.

Another prominent Sullivan was Anne Sullivan (1866-1936), the American teacher and companion of Helen Keller, the deaf and blind author, and activist. Sullivan played a crucial role in Keller's education and development, helping her to communicate and learn despite her disabilities. Her dedication and innovative teaching methods have made her an inspirational figure in the field of education.

In the 20th century, Ed Sullivan (1901-1987) was an influential American television personality and host of the long-running variety show "The Ed Sullivan Show." His program helped introduce many famous musicians, comedians, and performers to a national audience, earning him the nickname "The Great Stone Face" for his impassive demeanor during performances.

Other notable figures throughout history with the first name Sullivan include Sullivan Ballou (1829-1861), an American Civil War officer known for his poignant letter to his wife before the First Battle of Bull Run, and Sullivan Broderick (1818-1859), an American politician and leader of the anti-immigrant and anti-Catholic Know Nothing political movement in the mid-19th century.