The New York Tribune commented on the important partnership by referring to Duyckinck and Mathews as "the Castor and Pollux of Literature—the Gemini of the literary Zodiac".

Between 1844 and 1846, Evert became the literary editor of John L. O'Sullivan's The United States Magazine and Democratic Review, which moved from Washington, D.C., to New York in 1840.

He published Wit and Wisdom of Sydney Smith, with a memoir (New York, 1856); an American edition of Willroot's Poets of the Nineteenth Century (1858).

Immediately after the death of Washington Irving, Duyckinck gathered together and published in one volume a collection of anecdotes and descriptions of traits of the author, under the title of Irvingiana (1859); History of the War for the Union (3 vols., 1861-65); Memorials of John Allan (1864); Poems relating to the American Revolution, with Memoirs of the Authors (1865); Poems of Philip Freneau, with notes and a memoir (1865); National Gallery of Eminent Americans (2 vols., 1866); History of the World from the Earliest Period to the Present Time (4 vols., 1870); and Portrait Gallery of Eminent Men and Women of Europe and America.

The letter enclosed a newspaper clipping about an inappropriate joke allegedly told by Lincoln at the Hampton Roads Peace Conference.

[10] In January 1879, a meeting in his memory was held by the New York Historical Society, and a biographical sketch of Duyckinck was read by William Allen Butler.

[12] Charles Frederick Briggs noted Duyckinck's ability in the "art of puffing", heavy praise for works that did not necessarily merit it.