Lossing was born in Beekman, New York, and began his career as a journalist in Poughkeepsie. He later moved to New York City, where he became involved in the literary and historical community. He was a member of the New-York Historical Society and served as its librarian from 1848 to 1860.
In addition to his historical works, Lossing also wrote several books on biography and travel. He is also known for his contributions to the popular magazine Harper's Weekly, for which he wrote articles on a variety of historical and cultural topics.
Lossing's work is noted for its accuracy, detail, and vividness. He was one of the first historians to use illustrations to enhance the reader's experience, and his books are considered valuable resources for anyone interested in American history.