Mount Marcy's stature and expansive views make it a popular destination for hikers, who crowd its summit in the summer months.

The first recorded ascent of the mountain was made by a party led by Ebenezer Emmons[a] on August 5, 1837, who named it after New York governor William L. Marcy.

One of the mountain's most notable ascents was made in 1901, when Theodore Roosevelt climbed it with his family, and learned during his descent that William McKinley was dying and he was to become President of the United States.

[7] In September 1837, the area was visited by poet and author Charles Fenno Hoffman, who proposed the alternative name Tahawus, a Seneca term which has been translated as "cloud-splitter" or "he splits the sky".

[13] Lake Tear of the Clouds, at the col between Mounts Marcy and Skylight, is often cited as the highest source of the Hudson River.

[18] The earliest recorded ascent of Mount Marcy was on August 5, 1837, by a large party led by state geologist Ebenezer Emmons measuring the highest peaks in the region.

[26] Most of the Adirondack region, including Mount Marcy, had been sold to private landowners shortly after the American Revolution.

[28] On September 13, when it became clear McKinley was dying, Roosevelt was staying at Tahawus, and spent the morning ascending Mount Marcy with his family.

[31] Marcy's popularity as a hiking destination has steadily increased in recent decades, conflicting with the goal of keeping the mountain and the surrounding area as wilderness.

[36] The mountain can also be ascended at the end of the Great Range Trail, which begins at the Rooster Comb trailhead in Keene Valley.

This route is much more challenging and crosses the summits of the Great Range before merging with the Van Hoevenberg Trail, for a total distance of 14.5 miles (23.3 km) one way and 9,000 feet (2,700 m) of cumulative elevation gain.

The two southern routes meet at the Four Corners intersection at the col between Mounts Marcy and Skylight, from which both peaks can be accessed.

The lower slopes of Mount Marcy are covered by hardwood forests containing American beech, sugar maple, and yellow birch trees.

Botanist Edwin Ketchledge conducted an ecological study of the summits in the late 1960s and concluded the alpine plants were being destroyed by litter and trampling from hikers, after which habitat restoration projects were carried out in the 1970s.

[45] A variety of birds can be found in the spruce-fir forests of the upper slopes, including black-backed woodpeckers, golden-crowned kinglets, and white-winged crossbills, as well as mammals such as pine martens, porcupines, and red squirrels.

Birds that frequent the alpine zone of the High Peaks include common ravens, dark-eyed juncos, white-throated sparrows, winter wrens, and several species of warbler.

[47] Mammals that live in the alpine zone include American ermines, long-tailed shrews, and snowshoe hares.