The swamp metalmark has one generation per year which begins when the female selects suitable places beneath the downy leaves of swamp thistle (Cirsium muticum) to lay her eggs. The minute pale green eggs require from two to four weeks to hatch and the larvae (5-6 mm in length) feed a short time before hibernating. They over-winter on the ventral side, along the midrib near the base of the basal rosette of the swamp thistle.
The following spring the caterpillar resumes activity and attains maturity by early July. At this time it is green and covered with long whitish hairs. By late July or early August most adults have emerged from the pupal stage and may usually be found perched upon the low-growing grasses or slightly taller vegetation of the swamp lands. Their flight period ranges from late June to mid August. Depending on the size of the population the flight period may last 2-3 weeks, although most individuals probably live for only a few days. Dispersal flights tend to be short distances, weak and close to the ground.
Critical habitat features needed by the swamp metalmark butterflies include areas with open, low vegetation with an abundance of the larval food plant (swamp thistle) and suitable nectar plants. Nectar plants include mountain mint, black-eyed susan, swamp milkweed, shrubby cinquefoil and yarrow.