Acting mayor is a temporary office created by the charter of some municipal governments.

History

In many cities and towns, the charter or some similar fundamental document provides that in the event of the death, resignation, or removal from office of the mayor, another official will lead the municipality for a temporary period, which, depending on the jurisdiction, may be for a stated period of days or months until a special election can be held, or until the original end of the term to which the vacating mayor was elected. The charter may also provide for an acting mayor to serve in the event that the incumbent

Incumbent

The incumbent, in politics, is the existing holder of a political office. This term is usually used in reference to elections, in which races can often be defined as being between an incumbent and non-incumbent. For example, in the 2004 United States presidential election, George W...

 mayor is determined to be too disabled to continue to perform the duties of the office, either for a temporary period or permanently.

The position of acting mayor is usually of considerably more importance in a mayor-council form of municipal government, where the mayor performs functions of day-to-day leadership, than it is in a council-manager form of government, where the city manager

City manager

A city manager is an official appointed as the administrative manager of a city, in a council-manager form of city government. Local officials serving in this position are sometimes referred to as the chief executive officer or chief administrative officer in some municipalities...

 provides day-to-day leadership and the position of mayor is either a largely or entirely ceremonial one.
In some jurisdictions, the mayor's successor is not considered to be an acting mayor but rather fully mayor in his or her own right, much in the manner that the Vice President of the United States

Vice President of the United States

The Vice President of the United States is the holder of a public office created by the United States Constitution. The Vice President, together with the President of the United States, is indirectly elected by the people, through the Electoral College, to a four-year term...

 is not styled or considered to be Acting President

Acting President of the United States

Acting President of the United States is a reference to a person who is legitimately exercising the Presidential powers even though that person does not hold the office of the President of the United States in his own right....

 following the death or resignation of the President

President of the United States

The President of the United States of America is the head of state and head of government of the United States. The president leads the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces....

, but rather President in every sense.