In English, name Casey means – From a polish word meaning Proclamation of peace. A diminutive of Casirnir, Cassandra, or Catherine. Popularized as a boys name by the American folk song Casey Jones.. Other origins for name Casey include – English, Irish, Celtic, Gaelic, Spanish, Irish, French, Gaelic, Irish. Name Casey is a unisex name and can be used for a boy or girl name (male or female).