Crants was chief financial officer of a real estate company in
Nashville, Tennessee. He was its treasurer. As of 2015, it is the largest prison management company in the nation. By 2016, Corrections Corporation of America (CCA) along with
Geo Group were running "more than 170 prisons and detention centres". CCA's revenues in 2015 were $1.79bn. Shortly after the
September 11 attacks in 2001, Crants co-founded the Homeland Security Corporation with one of his sons, D. Robert Crants, III. Crants was its chief executive officer, while Joseph S. Johnson is president. ==Personal life and death==