The leaves of rocky mountain maple are typically lobed with 3-5 prominent, pointed lobes. They are medium to bright green throughout most of the year, transforming into striking shades of yellow to brick red in the fall. The leaves are approximately 2-4 inches (5-10 cm) long and wide. They have a smooth texture with a slightly glossy surface and distinct vein patterns radiating from the central point. The edges are finely serrated, enhancing their distinct appearance.

The flowers of rocky mountain maple are small and green, blooming in April. They are dioecious, meaning individual flowers are either male or female. The arrangement is simple, lacking prominent petals, which may lead to their seeming insignificance. These flowers are pollinated by insects and lack a noticeable scent. They later give way to striking red winged samaras in late summer. The flowers are critical for identification due to their unique reproductive structure and insect pollination.

The stem of rocky mountain maple is notably smooth and exhibits a striking red hue during the winter months. Typically slender, it may vary in thickness but often measures around 0.2 to 0.5 inches (5 to 12 mm) in diameter. The branching pattern of rocky mountain maple is relatively sparse, with branches emerging from the main stem at irregular intervals. This red color and smooth texture are crucial identification features, particularly visible during the colder season.

The fruit of rocky mountain maple is a distinctive red winged samara, a type of dry fruit that facilitates wind dispersal. Typically appearing in late summer, these samaras are marked by their paired wings that radiate outwards, measuring approximately 1 inch (2.5 cm) in length. The wings have a papery texture and a prominent red hue that offers a visual allure. The fruits emerge following inconspicuous green flowers that are insect-pollinated. As rocky mountain maple is dioecious, with separate male and female plants, only the female plants bear these samaras.