O'Brien's area of specialization is race relations and social inequality. O'Brien served on the faculty of Christopher Newport University, College of William and Mary, University of Richmond and State University of New York (SUNY) - Brockport before coming to Saint Leo in 2011. O'Brien also did research work for Harris Interactive, Perceptive Market Research, and the Ohio Commission on Racial Fairness.
O'Brien's most recent work examines race and gender and hip hop (especially Asian American/African American relations), as well as white privilege both co-authored with Dr. Ninochka McTaggart, including the newest book White Privilege: The Persistence of Racial Hierarchy in a Culture of Denial (Cognella, 2020). O'Brien’s other books include Whites Confront Racism (Rowman & Littlefield, 2001); White Men on Race (Beacon, 2003) with Joe Feagin, winner of Choice 2004 Outstanding Academic Book Award; The Racial Middle (NYU Press, 2008); and Race, Ethnicity, Gender and Class: The Sociology of Group Conflict and Change (Sage, 8th edition, 2019) with Joseph Healey. O'Brien has also authored numerous book chapters and articles, and writes for the blog Racism Review. O'Brien is a member of American Sociological Association and Southern Sociological Society. She serves on the board of All Together Williamsburg (a group facilitating community race dialog) and leads periodic community workshops on white privilege and racism.
*Created course in Saint Leo course catalog
**Created course in Saint Leo course catalog and created online version of the course