Ballard achieved national stature for his work on clean energy, water, and infrastructure. He doubled the number of sister cities for Indianapolis, visited all eight sister cities, and he and his wife, Winnie, were honored as the International Citizens of the Year in 2014. He also began the VEX Robotics Championship in the city of Indianapolis, which later expanded to the state championship. He is in the VEX Robotics Hall of Fame.
In addition to his bachelor's degree in economics from IU, Ballard earned a master of military science degree from the Marine Corps University and was awarded honorary doctorates from Butler University and Marian University. After his time as mayor, he served on numerous boards, including the Women’s Fund, the Indiana Veterans Affairs Commission, and the Indiana War Memorials Foundation. He was a co-founder of Indy Women in Tech, an organization that provides funding for women to train for tech careers and also sponsors STEM days for middle school girls; Ballard remains on their board. He has been a visiting fellow for civic leadership and mayoral archives at the University of Indianapolis and continues to serve on the President’s Advisory Board for Marian University.
A Persian Gulf War veteran, his military decorations include the Legion of Merit, the Meritorious Service Medal with Gold Star, the Joint Service Commendation Medal, the Marine Corps Expeditionary Medal, and the Saudi and Kuwaiti Liberation of Kuwait Medals. He has written two books: The Ballard Rules: Small Unit Leadership and Less Oil or More Caskets: The National Security Argument for Moving Away from Oil, published by Indiana University Press. Ballard and his wife Winnie have been married for 38 years and have two children, Erica and Greg Jr., both of whom are IU graduates.