Through Henry IV Part 1, William Shakespeare utilizes facades to reveal his character's true identities. For the sake of brevity, I'm going to focus my analysis around Hal.
Initially it seems as if Hal does not take ownership of his princely responsibilities. He steals and drinks and takes advice from a seemingly drunken oaf. He wastes his time at the tavern listening to Falstaff blabber on, glamorizing himself and his lifestyle. But Falstaff acts as a Foil to King Henry. He is active. He lives life, he does not simply sit back passively and judge and wonder why things are falling to pieces. Hal recognizes this. He sees his father and knows that he doesn't want to be like him. He doesn't want to rule like him. Hal recognizes that his father has no understanding of common man's struggles. There is such a vast disconnection between royalty and the others that it would be impossible to rule effectively. And Falstaff helps him to realize this. Falstaff's tales, although at times far-fetched and absurd, reveal a great deal of wisdom. And he didn't learn this from watching the world burn around him, but rather, by experiencing the world. This seems to intrigue Hal. And from this Hal derives his identity, or more accurately "future" identity. He is the Prince, heir to the throne, and future king and he, from the beginning, is motivated to distance himself from his father's antics in ruling and reform public perspective of the king.
Hal does so by only allowing people to see the side of him that he wants them to see, which is made evident in his first soliloquy. He claims, "I will imitate the sun,/ Who doth permit the base contagious clouds/ To smother up his beauty from the world" (1. 2. 204-6). Here, Shakespeare makes a pun on "sun," so as to suggest Hal will play the role of a disobedient son. Which is intriguing. Hal, the future king, heir to the throne, intentionally wants to make himself detestable in his father's eyes. He wants his father to see him as contaminated by the base clouds that are his friends. The disgrace he brings himself causes his father to shame him by (almost) completely denying that Hal is his son. This removes pressure from Hal. If he appears to not take his future occupation seriously, no one else will take him seriously. However, it's interesting that Hal says these base clouds would "smother up his beauty from the world." Hal doesn't want to grow up under the scrutinizing gaze of the public eye; it's as if he is using his misdeeds and offenses to blend in with the rest of the people. He doesn't want to be placed on a pedestal and be worshipped by his people, he wants them to recognize that he too is imperfect, just as they are. Hal may pretend to disregard his duties, but in actuality, he spends the majority of the play using this guise to cover his true intentions. From the beginning, he focuses solely on how he will become the best ruler he can be. And by living in this image as a thief, Hal will be able to accomplish his true goal of finding common ground between the crown and the commoners.
As the play progresses, Hal maintains his connection with Falstaff and his fellow criminals, but displays more kingly qualities. When confronted by his father, Hal realizes that he must rise to the occasion and become the Prince. Not just in title, but in action. He cannot hide himself any longer, and he promises to repay his debts: "I will redeem all this on Percy's head,/ And in the closing of some glorious day,/ Be bold to tell you that I am your son" (3. 2. 137-39). And by the end of King Henry IV Part 1, Hal fulfills his promise to his father, just as he fulfilled his promise to "pay the debt [he] never promised" (1. 2. 216). And from this point forth, he asserts himself as Prince and reveals his worthiness of the crown. He deserves the title because he is willing to fight for it. But he not only fights for his title, but for his father, for the King, for his kinsmen, for his country. He saves his father's life and triumphs over Hotspur, and does so humbly. He almost mourns Hotspur's death, recognizing that the world lost a fine warrior. But also, Hal redeems himself to his father, his country, and proves that he cares for his people and is prepared to take any measure necessary to protect them and promote their well being.
On that day he truly becomes king, "As if he mastered there a double spirit/ Of teaching and of learning instantly" (5. 2. 66-67).
