The senior administrator may be considered a second-in-command to a politically appointed cabinet minister or other government official (e.g. in the United States), or they may be considered a head or chief executive of a government department (e.g. a permanent secretary).
Some systems of government have both types of position, as in the United Kingdom where the title has been in use since the 17th century.
In France the Undersecretary of State (sous-secrétaire d'État) was a governmental role created during the Hundred Days and institutionalized in 1816.
In the Holy See, undersecretary is a title given to senior administrative officials working in the dicasteries of the Roman Curia.
In Hong Kong, undersecretary is a position created in 2008 to work closely with bureau secretaries and top civil servants to implement the Chief Executive's policy blueprint and agenda in an executive-led government.
Undersecretaries occupy gazetted civil service posts in India, unlike in some Western democracies, where they are political appointees.
An undersecretary will typically report to a deputy secretary, or a director to the Government of India.
In the Spanish Government, the Undersecretary is a political appointee charged with the daily representation of a ministry, the management of the common services and personnel.