He first appears in the play's third scene, when he storms onto the stage the morning after a hard night out, complaining about the sombre melancholy that hangs over his niece's household.

This immediately establishes Sir Toby at the opposite pole from the languishing melancholy which dominated the first scene (including Orsino's speech, "If music be the food of love..."), identifying him as a force for vitality, noise and good cheer, as his name suggests.

The plot against Malvolio is generally considered a comic highlight of the play, but critics have often complained of its cruelty.

Indeed, part of Malvolio's complaint is that Sir Toby and his companions are not acting like noblemen by drinking and singing, but like "tinkers" in an "alehouse".

His appreciation of Maria, though couched in terms that might not please every woman: "She's a beagle, true-bred" (II,3), and eventual marriage, shows that he thinks his title of no particular account compared to his love for her.