commissioner

n. official representative; head of a department; member of a commission; elected government official

Commissioner is a designation that may be used for a variety of official positions, especially referring to a high-ranking public (administrative or police) official, or an analogous official in the private sector (e.g. the highest executive position of many North American sports leagues).
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Noun
1. a government administrator
(hypernym) administrator, executive
(hyponym) bank commissioner
(derivation) commission
2. a member of a commission
(hypernym) member
(member-holonym) committee, commission

(n.)
An officer having charge of some department or bureau of the public service.
  

(n.)
A person who has a commission or warrant to perform some office, or execute some business, for the government, corporation, or person employing him; as, a commissioner to take affidavits or to adjust claims.
  

The European Commission is composed of 20 independent members, each responsible for specific policy areas and assisted by an administration. Commissioner António Vitorino is in charge of justice and home affairs. (See António Vitorino website)