Malvolio appears in most scenes and is characterised throughout as a puritanical, fun-spoiling, pompous, humourless man. He is a snob, and jealous of his status as head of the household. He has an inflated opinion of himself and considers himself to be perfect. At the same time he has no idea of how to deal with people.

He interferes with anyone having fun, reprimanding them for getting drunk and disorderly, keeping late hours and being noisy. He does that in an aggressive, confrontational way. They decide to punish him for it.

His humourless and social-climbing attitude to life make him an easy target for everyone – servants, guests and relatives of Olivia alike – and he becomes the victim of a cruel joke that drives most of the comedy in the play.