Laban's father, Bethuel, was the son of Nachor, Abraham's older brother. In addition, Laban was thrice related by marriage to Abraham's family: his sister Rebecca married Isaac, and his two daughters, Leah and Rachel, both married Jacob. Thus Laban was Abraham's great-nephew, Isaac's cousin and brother-in-law, and Jacob's uncle and father-in-law.
Laban lived in the city of Charan in Mesopotamia (Aram Naharaiim, the area between the Euphrates and the Tigris rivers in modern-day Iraq/Syria/Turkey), where Abraham's father and brother and their families settled after accompanying him on the first leg of his journey from Ur Casdim to the Holy Land. We first encounter Laban welcoming Abraham's servant Eliezer when the latter comes to Charan to find a bride for Isaac. A generation later, Isaac and Rebecca send their younger son Jacob to Charan to "take a wife from the daughters of Laban, your mother's brother."
Jacob falls in love with Rachel, the younger of Laban's daughters, and works for seven years tending Laban's flocks to earn her hand. But Laban replaces Rachel with her older sister Leah on the wedding night, Jacob discovering the deception only the next morning. Laban consents to give him Rachel in marriage as well -- in return for an additional seven years of labor. For the many deceptions that accompany this incident, as well as numerous other ways in which Laban attempts to swindle Jacob in the twenty years that his son-in-law is in his employ (Jacob works for an additional six years to earn flocks of his own), Laban is known in Midrashic literature as Laban HaRamai, "Laban the Deceiver". Yet Jacob boasts that, in the end, he bested his father-in-law at his own game, turning his deceptions against him to earn for himself the great wealth with which he returns from Charan to the Holy Land..
Laban tries to prevent that return at all costs, or, at the very least, to compel Leah, Rachel and their children to remain with him in Charan; when Jacob and his family flee Laban's home, he and his sons chase after them to force their return. It is for this reason that Laban is described as one of Israel's most dangerous enemies, for he sought to nip the fledgling nation in its bud, when its entire history was concentrated in the first Jewish family. In the end, Laban and Jacob make a truce on Mount Galed, where they erect a mound of stones as a testimonial that "I will not pass over this mound to you, and that you will not pass over this mound and this pillar to me, for harm," following which Laban returns to Charan.
This is the last event of Laban's life described in the Torah, at least under the name "Laban." But according to the Midrash, Balaam, the Aramite prophet summoned by the Moaboite king Balak to curse the Children of Israel on the eve of their entry into the Holy Land, is the very Laban who sought to prevent their departure from Charan so many years earlier. Indeed, says the Midrash, the "wall" against which Balaam's ass crushed the prophet's leg on his journey to the Plains of Moab to course the Israelites (see Numbers 22:25) is the very mound of stones erected by Laban and Jacob on Mount Galed to attest to the vow which Balaam was now violating with his journey. According to this, Laban/Balaam was more than 400 years old when he was killed in Israel's war on Midian shortly after his attempted cursing of the Jewish people.
The name Laban means "white". According to the Kabbalah, Laban represents loben ha-elyon, the "supernal whiteness" that transcends all "color" and classification. Thus "Laban" embodies the power of transformation -- because it is beyond classification, it bridges opposites and can transform a thing into its very extreme. This is how Balaam's divine gift of prophecy (our sages go so far as to equate his prophetic power with that of Moses!) could reside within such an evil person, and how, on the other hand, his virulent curses could be transformed in his very mouth into blessings, and this arch enemy of Israel even ends up issuing the most important of the Torah's prophecies (Numbers 24:15-25) -- the promise of the future redemption by Moshiach.