In the novel The Kite Runner, the author describes when young Amir and Hassan enter into a kite flying competition. The Kite Runner position is taken by Hassan, Amir's best friend and the son of their family servant. It is a position of servitude, which Hassan takes willingly and joyfully for his friend. Following a tournament, Amir witnesses Hassan get raped by another boy, and their relationship grows distant immediately.
Years later, in an attempt to reconcile, Amir travels back to Afghanistan to find Hassan, and he eventually saves the man's son from the now grown-up boy who had raped Hassan. Amir adopts Hassan's son and takes him to America. At the end of the novel, he volunteers to run the boy's kite for him. The position, and by extension the title, are meant as loving servants, willingly taking a lower position to help raise someone else up. That is what Hassan had done for Amir, which Amir feels like he betrayed. Now, Amir does this for Hassan's son, promising to love him and raise him up well, as a servant father.