Professor Preston in the author of Racial and Ethnic Politics in California, volumes I and II; The New Black Politics; and The Politics of Bureaucratic Reform: The Case of the California State Employment Service. He has been Associate Editor of the National Political Science Review and Urban Affairs Quarterly ; he has also been a reviewer for numerous professional journals and the National Science Foundation. He was President of the Western Political Science Association and has served as Vice-President of the American Political Science Association. In addition, he has also served on the Board of the Southern Christian Leadership Conference and on a Task Force of the Los Angeles Urban League. 

Professor Preston has also received outstanding teaching awards from the Mortar Board and the Department of Black Students. He frequently chairs panels and is a participant in conferences across the country discussing racial and ethnic politics in big cities, particularly the politics of Los Angeles and Chicago. He received his doctorate from the University of California, Berkeley; he joined the USC faculty in 1986, after spending 13 years at the University of Illinois-Urbana.