Ferris Bueller
Bueller. Bueller.
The name rings out over the school tannoy at role call, and not only does this create one of the most iconic lines - if twice repeating the same last name can be considered to be a line - in a John Hughes movie. Ferris Bueller is a teen hero who is smug, charming and charismatic, and also the master of the art of truancy. Ferris is also very appealing because his is disobedient and a rule breaker but never really a problem. He is extremely innovative, as witnessed by his contraption designed to prevent being discovered as a truant should anyone come to his home. He is the poster child for every one of us who has wanted to cut school and get out into the world and do something wilder that sit in school counting down the hours until graduation and the very last bell rings.
Ferris is aware that his high school days are coming to an end, but not only that, the times that he has spent with his girlfriend and his best friend are also ending because they are all going to be attending different colleges. Ferris is a popular kid and also a very good friend, for example, he offers to take the blame for the mileage on the Ferrari because he knows that Cameron's father will bully him and become abusive when he finds out.
The appeal of Ferris Bueller is that he does very little harm; sure, his actions could injure someone, or cause an accident, but they don't and so he is the kind of unlikely hero that we all root for. Even his sister, whom he frustrates enormously, finally comes to understand what makes her brother tick, and comes to appreciate him for it.
Mr Rooney
Mr Rooney is the hapless school principle who is always a loser when it comes to outwitting Ferris. He is the kind of man for whom the glass is not just half empty but the liquid in it tastes horrible. If there's a dog poop to step in Rooney will step in it; he is just that kind of man.
For some reason, discovering Ferris' absence on this occasion is the straw that breaks the camel's back, and probably because he knows that Ferris will graduate soon, and therefore not be under his authority or control anymore, he feels compelled to finally get the better of him and catch him out playing truant. Mr Rooney knows with every fiber of his being that Ferris is cutting school to have fun and not genuinely sick, but he almost gets arrested trying to prove it. He is always a step or two behind Ferris and at the end of the film is humiliated and a laughing stock as he rides the school bus, disheveled, back to school
Jeanie Bueller
Jeanie is Ferris' sister and one of the few people in the world who sees through her brother and his constantly going against authority, although it seems also that she is a little jealous that he is disobedient, willful, and gets away with every plan he ever makes to outwit an adult in a position of power. She is as intent on catching him out as Mr Rooney is - at least until the very end of the film when she has to marvel at her brother's ingenuity. Even when she gets the opportunity to get her brother into trouble finally, she decides to side with him against Mr Rooney. Jeanie also manages to best Mr Rooney for herself which seems to boost her self confidence and also make her feel a strange allegiance to her brother.
Sloane Peterson
Sloane knows that the telephone call from her "father" about the death of her grandmother is false because both her maternal and paternal grandmothers have passed already. She is a good student and a well-behaved girl but she is always up for an adventure with her boyfriend. She and Ferris have a great relationship and enjoy spending time together. Like Ferris she knows that their relationship will probably end at the end of high school, but she wants to make some amazing memories to take her into college. Sloane is fun and always willing to go along with Ferris' plans.
Cameron Frye
Cameron is a pessimistic and gloomy young man who is the opposite of Ferris. We learn later that this tendency to always look at the worst case scenario is because he has an abusive father, and also because he lacks self esteem, despising himself for not having stood up to his dad yet.
When the odometer on his father's Ferrari goes up and up, because of the garage attendants taking it out for a joyride, he will not let Ferris take the blame, but decides to use the ultimate destruction of the Ferrari as the opportunity he has been looking for to finally stand up to his father. Even it the confrontation goes very badly he will at least be able to feel better about himself, and feel less guilt about having never stood up for himself before.