A licensed psychotherapist with his own practice, Bannister joined the Carolina House staff after completing residencies in clinical social work at the Duke University Medical Center and Duke University Counseling and Psychological Services. During graduate school, Bannister was awarded the Duke Scholarship, providing full tuition for graduate work in divinity and was named the Kennedy Foundation Scholar for theological study. He also was named as the Edelman Foundation Scholar for Social Justice by the School of Social Work at UNC.
As a graduate student, Bannister worked to bring affordable housing to lower income and disabled persons and developed a participative and educative seminar for young people on HIV, AIDS and the role of the church. He continues to serve as a quadrennial commissioner of the United Methodist General Commission on Communication and is an active member of the People of Faith Against the Death Penalty in North Carolina. Music remains a passion for Bannister, and he signs and tours with the Duke Chapel Choir and with a local barbershop quintet, The Sons of the Prophets.