This moth is found locally throughout the British Isles, and flies in May and June.
The larvae mine various sedges, primarily glaucous sedge, although there are also records of the species using tufted hair-grass and (on the continent) blue moor-grass. The larvae are very distinctive, with two rows of red dorsolateral red spots. The colouration can be seen whilst it is within the leaf-mine.
Larval feeding commences in autumn as the early instar larval mine descends from the tip of the leaf. The mine is extended, filling in an area between the leaf edge and the midrib. Brown frass remains within the mine and is deposited in a trail behind the larva as it mines towards the base of the leaf.
The larva overwinters in its mine, but unlike most other Elachista species does not change its leaf with the arrival of spring. Instead the mine is extended further, sometimes filling the leaf width.
On leaving the mine, the larva secures itself to the upper surface of a leaf by means of a silken thread looped around the abdomen prior to pupation.