Dr. Trefry began teaching at Sacred Heart University in 1994. From the mid-1980s until 1999 when she began teaching full-time, she worked with a consortium of independent consultants, specializing in change management, performance appraisal systems, and management training. She had previously worked in senior management positions in large public library systems in Kansas City, Kansas and suburban Washington, D.C.. At Sacred Heart University Dr. Trefry has served as MBA Director, Luxembourg Programs Liaison, and Chair of the Management Department.

Her areas of teaching include leadership,organizational behavior, cross-cultural management and managing change. She teaches primarily in the MBA program, both in Connecticut and Luxembourg.

Dr. Trefry's research interests focus on cross-cultural issues and change management. She has presented her research at academic conferences, both in the United States and in Europe.