In 1838, Lossing moved to New York City seeking greater opportunity as a journalist and illustrator. He edited and illustrated J.S. Rothchild's weekly "Family Magazine" from 1839 to 1841 and launched his literary career with the publication of his "Outline of the History of Fine Arts". In 1846, he joined William Barritt in a wood engraving business that became one of the largest of such firms in New York. His illustrations appeared in the New-York "Mirror" and several other periodicals. During this time, Lossing sat for a portrait by Thomas Seir Cummings (1804–1894), now in the collection of the Metropolitan Museum of Art, New York City.