Troy A. Villarreal - President and Chief Executive Officer
Troy A. Villarreal joined Medical City in October of 2013, and has more than 19 years of experience in healthcare. Prior to his arrival at Medical City, he served as CEO of The Medical Center of Plano.
Villarreal has a strong history of community service. He is a member of the Board of Directors of the Dallas / Fort Worth Hospital Council, a member of the Fort Worth Stock Show Syndicate and also serves on the Board of Directors of Cancer Care Services. Additionally, Villarreal has served in the past on the Boards of the Fort Worth Public Library Foundation and North Dallas Chamber of Commerce.
Villarreal is a Fellow in the American College of Healthcare Executives. He earned his BS in Psychology from Texas A&M University in 1989 and his MHA and MBA from the University of Houston-Clear Lake, Texas in 1994. Mr. Villarreal is married and has four children.
Carol Gregory - Senior Vice President & Chief Nursing Officer
Registered Nurse Carol Gregory’s prior leadership roles include critical care clinician, director of education, assistant director of nursing, vice president of hospital operations, and chief nursing officer and vice president of patient care at The Medical Center of Aurora and Centennial Medical Plaza, in Aurora, Colorado.
Gregory is active in several professional organizations, including the American College of Healthcare Executives (ACHE), the American Organization of Nurse Executives (AONE) and the Association of periOperative Registered Nurses (AORN). Her career achievements include being named a 2008 Finalist for the Colorado Nightingale Award for Excellence in Human Caring and a 2008 and 2010 Nominee for the Denver Business Journal Outstanding Women in Business Award.
Gregory received her Bachelor of Science in Nursing from the University of Michigan, her Master of Science in Nursing from Wayne State University and a Master of Business Administration from the University of Denver.
Mark Atchley - Chief Financial Officer
Mark Atchley joined Medical City after serving as senior vice president and CFO at Medical Center of Plano, where he oversaw all financial management and registration functions, health information management, case management, scheduling and information services. Atchley is an experienced financial executive with a demonstrated record of developing and implementing creative business solutions for more than 27 years. He has also held executive financial positions at Hospital Corporation of America (HCA), Encon International and Chapman Companies.
A graduate of Abilene Christian University with a degree in accounting, Atchley brings experience in financial management disciplines including treasury, national and worldwide tax planning, and administration and payroll.
Keith V. Zimmerman - Chief Executive Officer, Medical City Children’s Hospital
Keith V. Zimmerman was named CEO Medical City Children’s Hospital in December of 2012 as interim, and permanently in August 2013. Zimmerman has 23 years of healthcare experience, and joined Medical City as Chief Development Officer in January of 2011.
Prior to Medical City, Zimmerman was the System Vice President of Business Development at OhioHealth in Columbus, Ohio. Prior to OhioHealth, Zimmerman has held multiple operational and business development roles in healthcare.
Zimmerman holds a Master’s of Business Administration in Health Care Management from Regis University in Denver with Graduate Honors, along with an undergraduate degree in Business Administration from the University of Louisiana. Mr. Zimmerman is married with two sons.
Mark Hébert, M.D. - Chief Medical Officer
Mark Hébert has more than 30 years of physician insight and expertise as an active member of Medical City. Before becoming chief medical officer, he was a staff anesthesiologist at Medical City and a medical director of the hospital’s Ambulatory Surgery Center (ASC).
During his tenure as an anesthesiologist, Hébert was elected to medical staff president and chairman for the department of surgery, and served in numerous hospital committees including the Physician Wellness Committee, Pharmacy and Therapeutics Committee, Meditech Advisory Committee, Quality Improvement Committee and the Privileges and Credentials Committee.
Hébert received his medical degree from Southwestern Medical School in Dallas, and completed his residency training at Parkland. He is also a member of the Ambulatory Surgery Centers’ governing board and medical executive committee.
Jamie Youssef - Senior Vice President & Chief Development Officer
Jamie Youssef is Medical City’s Senior Vice President and Chief Development Officer. He joined Medical City in 2011, and has more than 11 years of experience in healthcare in hospital leadership and physician practice operations. Prior to joining HCA, Jamie served as Vice President of Integrated Healthcare Strategies in Columbus, Ohio, and Director of Operations at OhioHealth Practice Management Services.
As Medical City’s Senior Vice President and Chief Development Officer, Jamie is responsible for the overall direction, strategic planning, and business development for all service lines at Medical City.
Jamie received his Masters of Healthcare Administration from The Ohio State University.
Zach Mueller, DNP, RN, NEA-BC – Senior Vice President & Chief Nursing Officer, Medical City Children’s Hospital
Zach Mueller is Medical City Children’s Hospital’s Senior Vice President and Chief Nursing Officer. He joined Medical City in 2011, and has more than 15 years of experience in healthcare. As a Registered Nurse, Zach has worked as a clinician in oncology and in the emergency department, and has served in a variety of leadership roles including in director roles over education, pediatrics, and cardiovascular services. Prior to joining Medical City, Zach served as Associate Chief Nursing Officer at The Medical Center of Aurora in Colorado.
Mueller is active in several professional organizations, including the Emergency Nurses Association (ENA), and the American Organization of Nurse Executives (AONE). His career achievements include speaking nationally and internationality on a variety of nursing and healthcare topics, as well as being named a Dallas-Ft. Worth Great 100 Nurse in 2014.
Mueller holds two doctoral degrees, a Doctor of Nursing Practice and Doctor of Nursing from the University of Colorado, as well as a master’s degree in nursing, and two undergraduate degrees. He is board certified by the American Nurses Credentialing Center as a nursing executive, advanced.