Jedi Master

Jedi Master was the highest rank most Jedi could obtain for becoming part of the Jedi Council, the main interface between the Jedi and the government of the New Republic. It is reserved for those who have shown exceptional devotion and skill in the Force. The title of Sith Lord was on par with the rank of a Jedi Master.

Overview
The rank was usually achieved by Knights who successfully entered Padawans into knighthood. When a teacher felt that his or her Padawan was ready, the Council would usually promote the Padawan to Jedi Knight and the teacher to Jedi Master under the proviso that the pupil pass a series of tests, known as the "trials". The Master could then pick another apprentice. A Knight who hadn't taken a Padawan can also retake the trials to earn the rank; often the trials were much harder and often involved a few more tests. The rank could also be granted by the Jedi Council to a Knight for performing some extraordinary deed or service, although this was rare and often reserved for Padawans to become Knights.

Even rarer, and often frowned on, was for a Knight to assume the rank without the Jedi High Council's approval.