It is more water-oriented than the related northern redback salamander, and can often be found in and around water such as rain puddles, streams, swamps, and damp stream beds, whereas the northern redback tends to be found in damp ground, but usually not near open water.

[4] This salamander is yellow or yellowish-brown, with two black stripes running down the back which tends to break up after the base of the tail.

[4] This species prefers small rocky streams or seeps in forests, but may occur in moist areas far from running water.

[4] Also, some data suggest this species may be found on stony shores of small lakes and rivers.

[4] These enlarged teeth are used to help abrade the female's skin and introduce the secretions on the males mental gland, found on the chin, into her circulatory system, which stimulates her to mate.

[11] To deposit eggs on the under surface of a rock, the female must flip on her back to make cloacal contact with the substrate.

[12] Communal nesting in northern two-lined salamanders has been documented on several occasions and localities; New York,[13][14] in Ontario,[15] and likely in Ohio.

[12] Upon hatching, the gilled larvae are about 10 mm long, and remain in slow-moving pools, or less frequently, hiding in crevices between rocks and boulders in swift-flowing streams.

[4] The adults and juveniles tend to be restricted to the stream edges, hiding under rocks and other debris during the day.

The movements of juveniles and adults usually occurs in the first hour after dark, when they emerge from under their retreats and forage along the stream bank or forest floor.

Food items recorded include wood roaches, arachnids, worms, isopods, millipedes, centipedes, beetles, snails, springtails, flies, hymenopterans, sowbugs, midges, mayflies, annelids, stonefly nymphs, caddisfly larvae, thrips and rarely trout fry.

[24] Adults overwinter up to 80 cm deep into the soil of the stream bank in cold climates, but may remain somewhat active in southern regions, and may continue feeding during this period.

[4] Because of its small size and localized distribution around streams, the northern two-lined salamander is preyed upon by a variety of animals.