Beside Venus, Jupiter is one of the two beneficial planets, standing for every possible
positives. Being the father of all gods in old Greece (Zeus), he was told to be omniscient, wise
and merciful, though he also was the god of thunder and lightning.
In astrology, Jupiter is standing for luck, optimism and abundance, and of course Jupiter is a male planet. He is the ruler of Sagittarius.
Jupiter is traditionally associated to the Emperor, yet in recent times people tend to connect him to the Wheel of Fortune. To me, for unknown reasons...
In Mesopotamian mythology Jupiter was associated with Marduk, the famous patron god of Babylonia. Marduk was the Babylonian main god looking after state and royalty and in extension Jupiter became the planet of the rulers and stayed it ever since.
As mentioned before the Mesopotamian gods can not always clearly be connected to specific planets when their attributions often shift. While Marduk was most prominently linked to Jupiter Mercury was also called 'Star of Marduk' at times and, more seldom, even Mars. The Babylonian 'King Star' could also be Regulus, the brightest star in the constellation of Leo. It just shifted tho and fro, depending on the astronomer at work.
What stayed in all the 'Jupiter representatives' among the gods was not only the royal attitude but a creation myth with striking resemblances.
In the Mesopotamian myth the first generation of gods were created by the ur-god Apsu (depicted as a primeval deity made of fresh water) and the ur-godess Tiamat (a primeval deity made of salt water and the embodiment of primordeal chaos), and one day Apsu got so upset by the descendants of his creation that he decides to destroy them all. The god Ea got knowledge about the sinister plan and killed Apsu, provoking a furious Tiamat to go on the war path. Tiamat turned out to be a horrible warrior who had a legion of monsters at her hand and the gods seemed doomed. Marduk promised to save them if they would make him King of the gods and when they agreed, he succeeded in destroying Tiamat by splitting her body in half and creating heaven and earth from it.
This is very similar to the Greek myth in which Zeus fought against his father Cronos (who had
the habit of eating his children) and later the monsters sent by an upset Gaia.
(... with the difference that Marduk first created the human world while Zeus destroyed the proverbial Golden Age out of anger over Prometheus - thus a nice aspect of the evils of power abuse).
The Roman Jupiter was but another version of the Greek Zeus with no remarkable difference.