He wrote more than 35 nonfiction and fiction books for children, young adults, and general audiences, including more than 30 about American history.

He published his first book, Weird & Wacky Inventions, one year later, having initially written a manuscript for a fictional work that went into thousands of pages before discarding it in favor of nonfiction.

[4][5] The ALA Margaret A. Edwards Award recognizes one writer and a particular body of work for "significant lasting contribution to young-adult literature".

Murphy won the annual award in 2010, citing five nonfiction books published from 1992 to 2003: The Long Road to Gettysburg, The Great Fire, A Young Patriot, Blizzard!

According to the citation, "Murphy's well-researched books bring history alive through multiple narratives involving young people.

Primary sources, maps, photos, illustrations and dialogue reveal the drama of historical events, making Murphy's books fast-paced reading of particular interest for young adults.

[8] Murphy won the ALA award for children's information books, the Robert F. Sibert Medal, for The American Plague in 2004 and he was a runner-up for BLIZZARD!