A periodontist, Singh served in the US Army as a Colonel, one of a small number of Sikhs allowed to retain articles of faith, grandfathered in after a change in policy in 1984 forbidding soldiers from exhibiting their religion with "conspicuous" clothing or style of hair or beard. He is one of the only Sikhs with a turban in the US army. He has three daughters and a son. His family currently resides in Colorado. Although GB has retired from the US Army, he is still actively involved in supporting rights for future Sikhs to keep their article of faiths in the military.