He wrote over 30 books on a variety of subjects, including his detective novels about the character Dennis Tyler.
In 1941, Carter was appointed by President Franklin Delano Roosevelt to conduct investigation into the loyalty of Japanese American communities on the West Coast of the United States.
Carter hired Curtis B. Munson to compile the Report on Japanese on the West Coast of the United States.
The summarized version focused on the disloyalty of Japanese Americans and inaccurately represented the full report.
His books The New Dealers (1934) and American Messiahs (1935) remain valuable sources for historians of the New Deal era.