Emerson contributed to American literature by being at the forefront of bringing European—and particularly English—Romanticism to the United States under a particularly American guise called Transcendentalism. Transcendentalism wedded the nature-loving, tradition-rejecting ideas of the Romantic movement with the Puritan emphasis on individual conscience.
Emerson's Transcendentalism added to the Romantic notion that the divine was expressed in nature and the idea that nature provided a model for free, individualist thinking—the rose, for example, was wholly itself, not in anyway warped by traditions or the past. Although Emerson's particularly American expression of Romanticism rejected the European past, Emerson was, ironically, very popular in England, suggesting how much he relied on European precedents.
However, Emerson was no European. While a poet like Wordsworth might exalt nature and the common person, he had no idea once the French Revolution came to ruin that the common cottager could rise to become a great man: Emerson, in contrast, thought that any American (excluding Black slaves, because like all the transcendentalists, he opposed slavery) could rise to eminence.
Emerson contributed to the American literary scene through, with Margaret Fuller, founding a magazine call The Dial that disseminated Transcendentalist thought and writing to a wider audience.
Emerson's articulation of the idea of freeing literature and thought from the weight of the past influenced American writers from Melville to Whitman to forge their own paths and create a distinctly American voice.