A five-star rank with NATO code OF-10, it is equivalent to a field marshal of the armies of numerous countries, a general of the Army of the United States, a captain general of the Spanish Navy (Armada Española) or a Captain general of the Air Force in the Spanish Air and Space Force (Ejército del Aire y del Espacio).

A Captain General's insignia consists of two command sticks under five four-pointed stars below the Royal Crown.

Since King Charles IV's reign (1788–1808), the monarchs used captain general insignia when wearing uniform.

A few posthumous honorary promotions and honorary promotions of retired officers to this rank were also made, such as José Moscardó Ituarte (1956), Agustín Muñoz Grandes (1957), Camilo Alonso Vega (1969) or Manuel Gutiérrez Mellado (1994).

Some members of the Spanish Royal Family were promoted to the rank after periods of service and Queen Isabella II appointed her consort, Francis, Duke of Cádiz (1846).