2001-2004
Regents Professor of History, Texas A&M International University, Laredo, Texas
1995-2002
Dean, College of Arts and Humanities, Texas A&M International University, Laredo, Texas1991-95
Professor, Department of Political Science, Criminal Justice and History, Texas A&M International University, Laredo, Texas1985-91
Associate Professor, Division of Arts and Sciences, Laredo State University, Laredo, Texas1983-85
Director, Honors Program, Laredo Junior College, Laredo, Texas1978-83
Chairman, Division of Behavioral and Social Sciences, Laredo Junior College, Laredo, Texas1968-78
Instructor, Social Science Department, Laredo Junior College, Laredo, Texas1966-68
Graduate Assistant, Department of History, University of New Mexico, Albuquerque, New Mexico1965-66
Classroom Teacher, Menaul High School, Albuquerque, New Mexico