For much of her professional career, Landes held a number of contract research positions. In 1939, she became a researcher for Gunnar Myrdal's study of African-Americans. In 1941, she became research director for the Office of the Coordinator of Inter-American Affairs. In 1941 to 1945, she was the representative for African-American and Mexican-American Affairs on President Franklin D. Roosevelt's Committee on Fair Employment Practices. Meanwhile, she began to study the Acadians of Louisiana.
