Leland studied for two years in Germany, where he became fascinated with German culture. On his return to America he studied and then practiced law. In 1853 he turned to journalism and worked for a number of years on Barnum's Illustrated News, the Philadelphia Evening Bulletin, and Vanity Fair. He also edited Graham's Magazine, where he published the first of his German-English poems, “Hans Breitmann's Barty” (1857). Written in a mixture of German and broken English and first published in the 1860s and 1870s, the poems were later collected in The Breitmann Ballads (new ed., 1895).

After inheriting his father's estate in 1869, Leland abandoned journalism, preferring to pursue his interest in folklore, mysticism, and the occult. He lived mostly in Italy and Germany after 1884.