Multiple realities
(covers information from several alternate timelines)
Klingon chancellor, 2153

The chancellor of the Klingon High Council in 2153.

Chancellor was a title used both by nation-states as well as planetary governments to refer to their head of government.

In an alternate timeline, Adolf Hitler was the chancellor and Führer of Nazi Germany in 1944. (ENT: "Storm Front, Part II")

In the real world, Hitler became Reichskanzler (chancellor) of Germany in 1933 and in 1934 had the offices of Reichskanzler and Reichspräsident (president) united in his person. He was officially referred to as "Führer und Reichskanzler" until 1939 when his official designation was changed to simply "Der Führer".
The existence of an Ekosian Chancellery in TOS: "Patterns of Force" indicated that John Gill at some point used a similar model in leading the Ekosians. Onscreen, Gill was only referred to as Führer.

Since the mid-21st century, the government of the Klingon Empire was headed by a chancellor. (TNG: "Rightful Heir")

In 2151, Kalev was the chancellor of the Coridan government. (ENT: "Shadows of P'Jem" In the alternate reality, Magustav Pachangara was elected chancellor of Coridan in 2259. (Star Trek Into Darkness)

In the first draft script of "Shadows of P'Jem" (written while the episode had the working title "Untitled Andorians Return"), Kalev was once referred to (in dialogue) as holding the title of "Supreme Chancellor", termed a "Chancellor" on all other occasions.

By 2152, a nation-state on a planet was led by Chancellor Kultarey. (ENT: "The Communicator")

The same year, chancellor Trellit was a leader of the Torothans. (ENT: "Desert Crossing")

The Andorian Empire was also led by a chancellor. In 2154, the Andorian chancellor contacted the Aenar to arrange a meeting with Jonathan Archer. (ENT: "The Aenar")

In 2367, Avel Durken was chancellor of Malcor III. The position of vice-chancellor also existed. (TNG: "First Contact")

In 2368, Alrik served as chancellor of Valt Minor. (TNG: "The Perfect Mate")

In 2374, Gaumen held the office of chancellor of the B'omar Sovereignty. (VOY: "The Raven")

According to the script of ENT: "A Night in Sickbay" and the Star Trek Encyclopedia (4th ed., vol. 1, p. 443), the Kreetassans were led by a chancellor, heading the Kreetassan Chancellery.
In the script of DS9: "Emissary", the chancellor of an university on Earth contacted Benjamin Sisko.

See alsoEdit