Professor de Jong completed her bachelor's and master's degrees in New Zealand and came to the United States in 1993 to complete a Ph.D. degree at Pennsylvania State University. She held a fellowship at the Carter G. Woodson Institute for Afro-American and African Studies at the University of Virginia and teaching positions at George Mason University and the University of Wisconsin-Parkside before taking a position at the University of Nevada, Reno in 2002.
Her research and teaching focus on the connections between race and class and the ways that African Americans have fought for economic as well as political rights from the end of Reconstruction through the 21st century. She has written three books: "A Different Day: African American Struggles for Justice in Rural Louisiana, 1900-1970" (University of North Carolina Press, 2002); "Invisible Enemy: The African American Freedom Struggle after 1965" (Wiley-Blackwell, 2010); and "You Can't Eat Freedom: Southerners and Social Justice after the Civil Rights Movement" (University of North Carolina Press, 2016). Her current research examines tensions among family, community and justice that were evident during struggles to desegregate public schools in the mid-20th century United States.