Swamp milkweed grows in wet meadows, swamps, marshes, shores and riparian zones across eastern and central North America, from Manitoba and Quebec south to Georgia and Texas. It is a preferred host for monarch butterflies: in preference tests, over half of the eggs laid went on this species. Seeds germinate slowly and plants are often short-lived, commonly 2 to 5 years in gardens.
The Greenbelt Indigenous Botanical Survey cites Alyssa General recording that swamp milkweed stems were used as fibre for netting. The genus name Asclepias honours Asklepios, the Greek god of medicine, and incarnata refers to the flesh-pink flowers.