McCallum spent nearly three decades of his career in private practice handling civil litigation with an emphasis on complex business/class action litigation, health care/insurance matters and administrative regulatory proceedings. McCallum was confirmed by the Senate as Associate Attorney General, the third ranking official at the Department of Justice. In that role, he advised and assisted the Attorney General and Deputy Attorney General in the formulation and implementation of policy, as well as supervised five litigation components (the Civil, Tax, Antitrust, Environment and Natural Resources, and Civil Rights Divisions) and various non-litigation “program” components. McCallum served twice as the Acting Deputy Attorney General. Former President George W. Bush tapped McCallum in 2006 to serve as the U.S. Ambassador to Australia, a post where McCallum served for nearly three years, dealing with the multiple and varied issues affecting the U.S. relationship with one of its closest allies. McCallum received his J.D. from Yale Law School in 1973 after a degree in Jurisprudence with First Class Honors from Oxford University, where he was a Rhodes Scholar. He received his bachelor’s degree cum laude in history from Yale in 1968.