Aloe longistyla is a dwarf aloe, characterized by its exceptionally small rosettes. Plants are stem-less, usually solitary, but may well have 2 or 3 rosettes. The densely crowded, greyish-green leaves have a conspicuous waxy layer on their surfaces. The leaves are lanceolate, up to 150 mm long and 30 mm wide near the base. There are firm white spines of up to 4 mm long on both surfaces, and rows of these spines can also be seen along the leaf margins. Each of these spines has a white tuberculate base.

The inflorescences are dense, broad, cone-shaped racemes which appear singly or in pairs of up tot 200 mm high with very thick unbranched peduncles. Up to 50 pale salmon-pink to coral-red flowers are borne on these plants in the winter from July to August. Relative to the small size of the plant, the flowers are exceptionally large, up to 55 x 10 mm. An unmistakable characteristic of the flowers is that their upper halves are curved upwards to expose the unusually long stamens and styles that protrude for more than 20 mm from the mouth of the flower tubes. Fully exerted styles have a length of up to 75 mm, making them the longest known styles for any South African aloe.

As with other members of the Asphodelaceae, the fruit is a typical capsule and seeds are winged, also quite large for such a small plant. Seeds ripen normally around October to November. This aloe, when not in flower, may easily be confused with A. humilis and A. brevifolia which superficially look similar but their flowers do not posses the unusually long styles found on A. longistyla. For the untrained eye, it would be easier to distinguish these species when they are in flower.