Young King Saul

The question was:

Who was Saul before he became king?

Saul belonged to the Tribe of Benjamin. His father was Kish of the Matri clan (1-Samuel 10:21). The Tribe of Benjamin had fought a Civil War against the rest of the Israelites and been defeated (Judges chapters 19, 20). Most of its people had then been wiped out and it was probably still in stages of recovery. Saul belonged to a family of landowners. They had workers and work-animals of their own (1-Samuel 9:3) but still worked on the land themselves (1-Samuel 11:5). Saul and his son Jonathan were very well-trained and proficient in military matters (1-Samuel ch.14). They were known war-heroes. 
From the beginning Saul had been known as "a mighty man of valor" (1-Samuel 9:1).

cf.

2-Samuel (NASB) 1:
 22 From the blood of the slain, from the fat of the mighty,
 The bow of Jonathan did not turn back,
 And the sword of Saul did not return empty.
 23 Saul and Jonathan, beloved and pleasant in their life,
And in their death they were not parted;
They were swifter than eagles,
They were stronger than lions.

Saul was described as "head-and-shoulders" above other men. By comparison if today the average height is 5 foot 9 inches then Saul would have been close to seven feet tall!

1-Samuel 9:
 2 ...Saul, a choice and handsome man, and there was not a more handsome person than he among the sons of Israel; from his shoulders and up he was taller than any of the people.

Saul was extremely good-looking. Bands of young women would delay him on the way and find excuses to lengthen the conversation with him (Midrash Shmuel on 1-Samuel 9:12). He was also very modest and even shy. When it was announced that he was to be king he ran and hid (1-Samuel 10:21-22). Though a known warrior he gave the appearance of not being tough enough to rule (1-Samuel 10:27). The whole family of Saul were aristocratic. They were sticklers for doing the right thing and acting correctly (cf. 2-Samuel 6:20). The refinement and sensitivity of Saul and Jonathan were legendary and held up as examples (2-Samuel 1:23). The pedigree of Saul was without blemish. The Sages said that this was his undoing. He was too good. He failed to be ruthless when he needed to be and ended up being vindictive and cruel to the innocent (1-Samuel 22:19). David on the other hand was partially descended from Ruth the Moabitess. This trace of foreign blood, says the Zohar, made David sufficiently obdurate to rule over Israel and ultimately, through the coming Messiah, over all the world.
 Through his son, Jonathan, an everlasting covenant was made between the offspring of Saul and that of David (1-Samuel 14:22). the Future Messiah will come from David and one of his assistants will be a descendant of Jonathan.
The nickname of the USA before it became known as "Uncle Sam" used to be "Brother Jonathan."

"Shem MeShmuel" (the Sochatover Rebbe, a Chassidic Rebbe in Poland in the 1800s) says:

"It would seem that the point of their being two Anointed Saviors in the future, Messiah son of Joseph and Messiah son of David, is that the Messiah son of Joseph is destined to destroy the seed of Amalek and fight the War of Gog and Magog, and all the other wars that he is destined to bring to a successful close as the Sages spoke, "Esau cannot be defeated except by means of the descendants of Rachel" (Midrash Breishit Rabah 73;5). Then after the removal of the concealing darkness will shine the light of the Messiah son of David whose only mission is to bring knowledge of the Almighty into the world. It would seem that something of this nature was seen in the rulership of King Saul, prior to that of King David. The initial intention was that Saul finish all the fighting since he was descended from the Sons of Rachel [favorite wife of Jacob] and he was an [intended] prototype of the Messiah son of Joseph. After Saul came the Kingdom of David. This was a prototype of the future Messiah son of David whose goal should only be to increase the revelation of Divine Light [in the world] and to build the Temple"
 (quoted by Elyahu Yedid, "Shaul Bechir HaShem", p. 29).