Jacob (also known as Israel) was one of the two sons of Isaac, who was the son of Abraham. "Jacob" means "he grasps the heel" which is a Jewish idiom meaning that the "he" is a deceiver. This is exactly what Jacob was. He bought his older brother Esau's birthright with red lentil stew and got Esau's blessing by tricking his father.
Jacob had 12 sons and one daughter. He had 2 wives who were sisters, and had two concubines who were the maidservants of his wives. His wives were Leah and Rachel. Jacob favored Rachel over Leah. Their father, Laban, tricked Jacob into marrying Leah, who was the older sister. It wasn't the custom of Laban's people to give the younger away in marriage before the older, so he had Jacob marry Leah and then Rachel.