It forms a powdery thallus with variable colouration, ranging from pale green to straw-coloured, and grows on bark, mosses, wood, and rock surfaces in humid, sheltered environments.

Lepraria jackii has been recorded across Europe, North America, Asia, and Australia, preferring acidic substrates.

A related taxon, Lepraria toensbergiana, was initially described as a distinct species based on its production of toensbergianic acid,[4] but some researchers later synonymised it with L. jackii.

The reproductive structures consist of abundant soredia ranging from fine to coarse (up to 0.16 mm in diameter), sometimes with short projecting hyphae.

[8] This lichen grows on various substrates including tree bark, mosses, wood, and both siliceous and neutral rock surfaces, rarely occurring on soil or plant debris.