Casey, from the Irish O’Cathasaigh, is a common surname in Ireland originally meaning “vigilant” or “watchful.” At least six different septs of the name existed in early Ireland as both O’Casey and MacCasey.

These septs were each very significant rulers in their locations, primarily in Munster counties. The O’Caseys of west Dublin were the Lords of the Suathni. Another line of O’Caseys were erenaghs, or keepers of church revenue, in Clondara, County Roscommon.

The Dalcassian septs were seated at Liscannon, County Limerick, and near Mitchelstown, County Cork. In the 14th century, three bishops named MacCasey were seated at Clogher in County Monaghan.

John Keegan “Leo” Casey (1846 - 1870) was a poet, novelist and orator as well as a famous Republican in the Fenian Rising. Born in County Westmeath, John was learning under his father to become a teacher when he discovered the lure of the pen.

At the age of fifteen he wrote the famous song The Rising of the Moon to commemorate the Irish Rebellion of 1798. He later took on the pen name “Leo” and under it wrote extensively for the Nation newspaper. As a leader of the Fenian Rising of 1867, John was imprisoned for eight months. After his release he lived in poor health for a short time before his death on St. Patrick’s Day, 1870.

It was reported that between fifty and one hundred thousand mourners attended the beloved writer’s funeral.

Another famous O’Casey writer was 20th century playwright Seán O’Casey (1880-1964), pictured above.  Born John Casey, Seán adopted the Gaelic spelling of his name as his interest in the Irish nationalist cause grew. His famous works include Juno and the Paycock, set during the Irish Civil War, and The Plough and the Stars, which is set in Dublin during the Easter Rising of 1916. He wrote initially on political issues, attacking imperialist wars, but in his later career, the Dublin native became known for being one of the first playwrights to write about working-class Dublin.

Seán O’Casey’s daughter Shivaun O’Casey began her career as a scenic designer in theater before becoming an actress. She settled as a director and founded the O’Casey Theater Company in her father’s honor. Shivaun moved on to film and made a documentary, In the Shadow of O’Casey, about her father.

Also among the ranks of famous Casey writers is John Casey (1939-). A native of Worcester, Massachusetts, John is a famous American novelist who secured the National Book Award in 1989 for his book Spartina.

In the world of business, Liam Casey is the founder and CEO of PCH International, and Irish America’s Business 100 keynote speaker this year. His supply chain management company has grown to offices in Ireland, China, Singapore, the U.S., Brazil, the UK and South Africa.

William J. Casey (1913-1987) served under President Reagan as the Director of the Central Intelligence Agency (CIA). The Queens, New York native largely helped to shape foreign policy in the Reagan administration, particularly in reaction to Soviet activity. William succumbed to brain cancer in 1987.

Another Casey who carried the tradition of government service is Mary Ann Casey (1949-), an American diplomat. She is now retired after a career in foreign diplomacy as a Foreign Service Officer and U.S. Ambassador to Algeria (1991-1994) and Tunisia (1994-1997). Mary Ann has worked extensively in Northern Africa with a stint in the U.S. Embassy in Morocco as well as some time as a desk officer in Iraq.

In the world of sports, Conor Casey (1981-) is an American soccer player, currently a forward for the MSL’s Colorado Rapids. He recently earned attention on the international scale after scoring two goals against Honduras in the World Cup qualifier that pushed the U.S. team through to the 2010 World Cup in South Africa.

Currently ranked behind only Tiger Woods and Phil Mickelson is English golfer and another athletic member of the clan, Paul Casey (1977-). He is on the PGA tour and the European tour, at the peak of a professional golf career.