The character of Falstaff is of great interest in the subject of the undermining of authority. Falstaff's role in the play, as well as the society is complex. Through the course of the play, he earns the title of "King of Misrule". Right away, he becomes an obvious symbol of subversion. Regarding his role in the play, a claim can be made that he assumes the role of Fool. He is a Fool, for all intensive purposes.
Falstaff is a noble, recognized by the title "Sir John Falstaff", and yet by no means exemplifies that which is typically deemed noble. He is repeatedly associated with all that is traditionally 'common' and base in the culture of the English Renaissance. He eats and drinks in great excess, steals, and carouses - hardly behaviors suiting nobility.
This closer association with the common folk emphasizes his undermining of authority specifically when he assumes the role of King in his charade with Prince Hal (Act II, scene iv). Falstaff temporarily becomes the "Mock King", divulging his views on what his rule would be like.
The episode of the Mock King marks an important turn in the play. In it, the outcome of Prince Hal's rule is made evident. When the prince becomes king, he will become the proper authority that he needs to become, rather than merely a precocious youth. Specifically in this scene, Henry illuminates his plan to disavow himself from both Falstaff and his less-than-noble ways of life. In shedding himself from Falstaff's company, Prince Hal will shed himself from his youthful and 'common' ways of life. Thus, Prince Hal's change to ruler from youth is made, not in spite of Falstaff, but through Falstaff.
Why must Prince Hal prove himself so worthy? As he is the son of the King Henry IV, he would naturally be next in line for the crown. This should be enough. However, in wake of his father's ascension to the throne through illegitimate means (see Shakespeare's Richard II), Hal must find a new sense of legitimacy, so as to avoid merely following in his father's footsteps as a 'nobody king'. Therefore, he must prove himself worthy above and beyond normal standards.
Throughout the course of this play, Hal completes this task remarkably well. The prince acts as a sort of "anti-king" to fully present himself as the true king - deserving of the authority of rule over any other contender. This "anti-king" role is of note in the discussion of subversion. As each side of extremity is dependent upon the other, Hal must play to both sides to assert his legitimacy. At the outset of the play, Prince Hal sides with Falstaff in his merry ways of living: drinking, fraternizing, and other irresponsible behavior. Hal embraces subversion to the authority of his father, much to the king's dismay. However, as Shakespeare's play unfolds, the prince says himself that he intends upon denying any connection to Falstaff. In doing this, he will come to represent the proper extreme of authority.
Clearly, as represented in 1 Henry IV, a representation of subversion is seen as necessary in order to assert the notion of authority. In this sense, one can make the connection to the importance of festival during Renaissance England, in which authority is temporarily subverted. It offers the chance to reaffirm the authority by undermining it for a small period of time, much in the same way that Shakespeare represents the young prince who will become arguably one of England's greatest rulers.