Your Coaches

Meet Our Executive Coaches

The firm’s principals, Ellen Harvey, PhD, and Dinah Nieburg, PhD, have established a team of coaches with an average of 20 years coaching experience and deep expertise in working with international organizations. GCS coaches are valued not just for asking the right questions and listening well, but for providing the kind of individual and team coaching that results in lasting change.

Ellen Harvey

Ellen Harvey, PhD, is an executive coach and psychologist with 20 years of experience working with global leaders and multicultural teams. Ellen brings a smart approach grounded in research and real-world solutions. She connects particularly well with leaders with ambitious professional goals who find themselves in the midst of complex and changing environments. Ably combining the strategic with the practical, Ellen possesses extensive expertise in most aspects of leadership and management development, including strategic vision and planning, innovation, productivity, and interpersonal relations. Working with senior executives and their teams, Ellen helps clients develop focused goals, create synergies and solutions, and increase their capacity for growth and success. Ellen enables executives to lead with courage born from self-knowledge, effectively motivate their teams to realize their potential, and make wise decisions for the overall health of their organizations.

Dinah Nieburg

Dinah Nieburg, PhD, MISCP is an executive coach and psychologist who brings over 25 years of combined experience as a manager of multicultural teams, training and development specialist, psychologist, and coach. She has a special interest in helping her clients become adept people managers, learning to handle stress and improve work-life balance, and become more reflective and strategic in the face of their challenges and goals. She has developed cutting-edge management development and training programs and worked with U.S. and international clients throughout the world. Her background as an experienced manager combined with her skills as a psychologist allows her to appreciate the needs and challenges of individuals in a variety of leadership roles, and build a trusting and collaborative relationship in which development and change can occur.


Carol Blimline, PhD,

Focuses on performance and change management, leadership development, and strategic planning. She is also skilled at honing people’s time management skills and the organization of their work programs. As an executive coach, Carol employs a variety of assessment inventories and 360 feedback instruments.  In addition to her coaching work, she is a clinical psychologist in private practice in Rockville, Maryland, and coordinates an employee assistance program for government and business.

Jean-Yves Maillat,

A French national, is an executive coach and international management consultant with 30 years of experience in strategic planning, organization development, change/turnaround management, executive coaching, leadership development, team building, and management of client-oriented service units. Jean-Yves improves personal and organizational effectiveness through the diagnostic analysis of personal, managerial, and organizational issues, conducts assessment of client needs and requirements, and develops strategies to address them. He has coached executives of many nationalities with a wide range of cultural and professional backgrounds.

Peter Swain,  

IFC Certified Coach, and British national, draws on an extensive career in human resources management at the International Monetary Fund to offer targeted executive coaching services to new managers as well as mid-level and senior executives. At the IMF Peter managed employee recruitment, management development, training, organizational development, and career counseling services across the organization. He has engaged in extensive internal coaching, consulting, and mentoring of staff at all levels and, as a business advisor, guided departments in developing their strategic HR plans. Earlier in his career, he served as an economist in the IMF’s Western Hemisphere department.

Greg Su MBA

Is an experienced facilitator, learning & development, and management consultant with over 20 years of experience across a broad spectrum of industries and geographies.  He partners with his clients to draw insight and understanding on what will lead to sustainable effectiveness for them and their organizations.  Coaching engagements have ranged from increasing the client’s ability to influence effectively, to expanding their strategic thinking, to expanding their executive presence, role, and contribution to the organization.  His clients have included senior executives at Sprint Nextel, Howard Hughes Medical Institute, Astra Zeneca/MedImmune, Mitre, and the US Coast Guard.