Common yellowthroats are small songbirds that have olive backs, wings and tails, yellow throats and chests, and white bellies. Adult males have black face masks which stretch from the sides of the neck across the eyes and forehead, which are bordered above with white or gray. Females are similar in appearance, but have paler underparts and lack the black mask. Immature birds are similar in appearance to the adult female. First-year males have a faint black mask which darkens completely by spring.
The breeding habitats of these birds are marshes and other wet areas with dense low vegetation, and may also be found in other areas with dense shrub. However, these birds are less common in dry areas. Females appear to prefer males with larger masks.