Ochrosia haleakalae is a tree that grows 2–8 meters tall and is characterized by a glabrous texture and milky sap. The leaves are simple and arranged in whorls of 3–4 per node. The blades are elliptic to oblanceolate, measuring 3.5–19 cm in length and 1.3–6 cm in width. The apex ranges from acute to rounded and sometimes retuse, while the base is cuneate. The leaf surfaces are glabrous, and the margins are entire. Lateral veins are conspicuous, especially on the lower surface, and arise at nearly right angles to the midrib, with most secondary veins anastomosing prominently. The petioles are 0.8–2.56 cm long, and the stipules are absent. The flowers appear in relatively open inflorescences, each subtended by small, opposite, ovate bracts. The primary peduncles are 2.3–4 cm long, and the secondary ones range from 0.6 to 3 cm, with pedicels up to 5 mm long. The flowers are bisexual (perfect) and usually numerous. The calyx is deeply 5-lobed with ovate, imbricate lobes about 3–4 mm long. The corolla is salverform (a narrow tube with petals bent abruptly outward at right angles), 5-lobed, with a cylindrical tube and greenish-white to white, oblong-elliptic lobes. The tube is 10–11 mm long, with 7–11 mm lobes. Five stamens are inserted on the corolla tube just below the mouth but not exserted. The ovary is superior, with two units either distinct or basally connate, containing 2–4 ovules each; the style is connate in the upper third, leading to a bifid stigma. The fruit is drupaceous, firm, and fleshy, drying to become hard, typically with both ovaries maturing. The drupes (pictured) are yellow or plum-colored with brown streaks, robust, ovoid to lanceoloid-ellipsoid, often showing irregular ridges at maturity due to differential thickening of the exocarp. They measure (3.8–)5–6 cm long and (2.3–)2.8–3.6 cm wide. Each fruit contains one ovate, strongly flattened seed. It is found in dry to mesic forests, often growing on lava substrates between 700–1,200 meters.