Dr. Callender leads Memorial Hermann Health System, where he has spearheaded a multiyear transformation strategy to create greater value for the patients and populations it serves. Under his leadership in 2025, the system registered 1.8 million patient encounters, successfully launched Epic with a “good install” recognition, deployed AI tools to enhance clinical workflows, completed more than 50 strategic investments and 20 strategic partnerships, and provided $486 million in community contributions and charity care. His focus on organizational culture has yielded striking results since 2021, including a 37% decrease in total turnover and a 43% decrease in first-year turnover. In addition, the system has seen a 95% reduction in contract labor since 2022. One notable culture initiative that has grown under his leadership is the employee recognition platform, through which 88% of employees received recognition. Dr. Callender has also been a prominent voice on healthcare policy, participating in a CEO working group convened by U.S. Senator Bill Cassidy to evaluate healthcare legislation, advocating alongside Houston healthcare leaders to extend Affordable Care Act enhanced premium tax credits, and successfully advocating to expand state funding for healthcare apprenticeships. He also serves on the boards of the United Way of Greater Houston, the Houston division of the American Heart Association and the Greater Houston Partnership. He serves as a founding member of the board of directors of Longitude Health.
