I’ve learned through experience of playing different characters, some of whom were jerks, that when you play a character who is pretentious or obnoxious, in any way, it’s important to knock them down a peg.

Hill is describing an acting principle he arrived at after portraying abrasive or self-important figures: if an actor plays a “jerk” straight—without any self-awareness, vulnerability, or comic deflation—the character can become merely grating or one-note. “Knocking them down a peg” suggests building in moments that puncture the character’s ego, whether through humiliation, failure, or glimpses of insecurity, so the audience can keep watching with interest (and sometimes empathy). The remark also implies an ethical/aesthetic stance: performances shouldn’t glamorize arrogance; they should reveal its fragility and consequences, making the character feel human rather than aspirational.