The phrase "last hurrah" is an idiom in the English language used to represent a final action, effort, or attempt before some eventuality, such as death, retirement, or some other major change, renders further actions of that sort impossible. The origins of the idiom can be found in a 1956 novel titled The Last Hurrah by Edwin O'Connor, which is about a politician's last mayoral campaign. The idiom is, therefore, commonly used to refer to the final political campaign that immediately precedes a politician's retirement or death. It can also be used to refer to any other final act before a major change; a bachelor party, for instance, may be referred to as a "last hurrah" before marriage.
An idiom is a phrase that, because of popular use, comes to take on an understood meaning that differs from the actual meanings of the words that compose the expression. A "last hurrah," for instance, may literally refer to a last celebratory cheer before people return to life as usual. The expression is almost never used to refer to a final cheer, though, and is generally understood to refer to some final action before a major change. The connection between the literal and figurative meanings is, however, evident. The "final cheer" is a final act of celebration and a "last hurrah" is generally a final positive, pleasant act before something renders further such acts impossible.
Though the idiom is, because of its origins, often used to refer specifically to final political campaigns, it does have a variety of other possible uses. For instance, an aging athlete's final season or final game before retirement is often referred to as a "last hurrah." Likewise, a college student's final party before graduation, a director's final movie, or a business's final product line may all be described with this idiom. Its versatility and its prevalence in conversational English make it a widely-used and widely-understood expression.
"Last hurrah" is not the only idiom that can be used to refer to a final act of some form. The idiomatic expression "swan song" can, in many cases, be used interchangeably with "last hurrah." The expression "swan song," however, is more commonly used to refer to a final act before death because it originates in an ancient myth stating that the mute swan, silent over the course of its entire life, sings one song of great beauty immediately before death. The use of this idiom has expanded to include retirement and other events aside from death, but it still refers primarily to death.