Below is a small look at some of the many characters in the film.

Neil Perry A vulnerable, impressionable and ambitious young man. He's shy and nervous but is bursting to express his feelings. Neil has respect. Respect for Mr Keating and the other teachers, but mostly, respect for his father. This respect is Neil's undoing. (I don't want to say anymore for fear of ruining the movie!)
Todd Anderson Todd's the new boy at Welton Academy. His older brother was valedictorian of the school, which means Todd has big shoes to fill. Like Neil, Todd is very shy, and being new to the school means that he feels a little bewildered and out of place. We see a big change in Todd over the duration of the film. With help from the other boys, and Mr Keating, Todd comes out of his shell. At the end of the film we see the new Todd. The Todd who speaks out in protest, who won't sit down when asked and shows a great amount of loyalty to his new friends.
Mr Keating A former student and the newest teacher at Welton Academy, Mr Keating is very different to the other teachers. He doesn't stick to the syllabus, his teaching methods are very different, and he teaches them individuality. Keating teaches the boys to think and act for themselves. Individuality instead of conformity. He encourages them to take risks and break rules; to "make their lives extraordinary". Keating introduces the boys to the idea of Carpe Diem; whether thats a good thing or not is left up to you.
Charlie Dalton aka Nuwanda Charlie is the true rebel of the group. He is the class clown at the Academy and is somewhat of an exhibitionist. If something will get him attention, you can bet he'll do it. Charlie shows true loyalty to the Dead Poets Society and even turns on a friend for suggesting something that went against the Society's ideas.
Knox Overstreet Knox is the romantic of the group. He falls head over heels with Chris, only to realise she has a boyfriend, Chet, who makes it quite clear that he is to leave her alone. His membership to the Dead Poets Society, and Keating's 'Carpe Diem' teachings inspire him to go after Chris and what happens next is left up to you to decide.
Steven Meeks Meeks is very intelligent. He is the one who makes all the boys start a study group for their school subjects like Latin and Chemistry. He is very hesitant at the start to go along with the boys and the idea of the Dead Poets Society but once he got into it he really enjoyed himself.
Richard Cameron Cameron is part of the group but he isn't as willing to follow the others boys and Keating and let loose. He is very proper and has to do things perfectly. We see all the boys rip pages out of their books at Keatings command and sitting at the front of the class we see Cameron cautiously rip the pages out with a ruler. In the end Cameron is the one who gives in to the teachers and confesses everything, thus turning on his friends and Mr Keating.
Gerard Pitts Pitts is a minor character in the film. He is friends with the boys in the group but we don't really see much of him in the film. He appears to be a bit of a loner in the group - sitting back during the Dead Poets meetings etc. But this doesn't stop him joining the other boys and standing up for what they believe in.
Mr Perry Mr Perry is Neil's over bearing father. Some say he wanted the best for his son, for him to get a good education, serve in the army (just like he did) then become a doctor. Others argue that Mr Perry drove his son to the edge and made him feel that there was no way out.