He and Stan Marsh alternate as leader of their group. Kyle is evidently the only Jewish kid in town and is often mocked for it by Eric Cartman. He has a little brother (adopted) named Ike. His mother, Sheila, is very overprotective: she instigates a war between America and Canada in the feature-length movie South Park: Bigger, Longer & Uncut because of an extremely scatological R-rated movie.
Kyle's most notable catch phrase is "Oh, my God! They killed Kenny!"
He wears a bright green ear-flapped cap, a bright orange shirt, green pants and green mittens. He is rarely shown without his cap, but without it he has a bright red afro.