Females lay eggs at the tip of host plant leaves, depositing only two or three eggs on a plant before moving to another.
Caterpillars eat their eggshells after they hatch, then at night feed on catkins and leaves.
Third-stage caterpillars make a shelter from a rolled leaf tip in which to spend the winter. Two to three broods from May- September in most of its range, all year in Florida. Early in the season when few flowers are available Viceroys feed on aphid honeydew, carrion, dung, and decaying fungi. Later generations feed more often at flowers, favoring composites including aster, goldenrod, joe-pye weed, shepherd's needle, and Canada thistle. Moist open or shrubby areas such as lake and swamp edges, willow thickets, valley bottoms, wet meadows, and roadsides.