After completing his Juris Doctor at Yale in 1973, McCallum joined the Atlanta law firm of Alston & Bird. Philip Alston, one of the principals of this firm, was U.S. Ambassador to Australia under President Jimmy Carter from 1977 to 1981. McCallum remained with the firm for 28 years, before joining the U.S. Department of Justice in 2001 as Assistant Attorney General for the Civil Division. In this position, he oversaw litigation involving the defense of challenges to Presidential actions and acts of Congress; national security issues; immigration; benefit programs; commercial issues including health care fraud, banking, insurance, patents, debt collection; and the Food Drug and Cosmetic Act. In July 2003 McCallum was appointed Associate Attorney General. He served as Acting Deputy Attorney General from September to December 2004 and from August 2005 until he resigned on being nominated as Ambassador to Australia. In 2005 McCallum was accused of interfering with the government's prosecution of the tobacco industry by requiring Justice Department lawyers to cut their demand for an industry-sponsored smoking cessation program from $130 billion to $10 billion. During his ambassadorial confirmation hearings before the United States Senate, Senator Dick Durbin of Illinois raised this issue and demanded an investigation of McCallum's role. The Justice Department's Office of Professional Responsibility found no wrongdoing on McCallum's part. In her 2006 decision in the case, Judge Gladys Kessler placed limits on tobacco companies' abilities to market cigarettes, but found that a previous appeals court ruling prevented her from requiring the industry to pay for a smoking cessation program.
Australia
McCallum had never been to Australia prior to his appointment and had had no previous involvement with the country, or indeed with foreign policy at all. The position of U.S. Ambassador to Australia is traditionally held by friends or political associates of the President, rather than by career diplomats, since Australia is a close ally of the U.S. and the post is considered a highly desirable one. The previous Ambassador, Tom Schieffer, was a business associate of President Bush. In an interview with The Australian, a national daily newspaper, McCallum said that he had been attending seminars on Australian affairs since his appointment. "I feel that I have got a good grounding in the fundamentals of what is going on in a very, very important relationship to the U.S. with Australia, and I'm eager to learn and experience that firsthand", he said. He said that he would seek to meet and establish close relations with Australian politicians of all parties, including those critical of U.S. policies. McCallum's arrival in Australia ended an 18-month period in which there was no U.S. Ambassador in Canberra. Following Schieffer's departure to take up the position of Ambassador to Japan in January 2005, the U.S. was represented by a Chargé d'Affaires, Bill Stanton, who also departed Australia before McCallum's appointment. The long delay was caused by the Bush Administration's apparent inability to find a candidate who was suitably close to the President but willing to undergo the scrutiny which accompanies the Senate confirmation process. McCallum announced that he would resign his position following the inauguration of President Barack Obama in 2009, to make way for the next U.S ambassador to Australia and---as he was not close with Senators McCain or Obama---iterated his view that it is important for a US-Australia ambassador have a close relationship with the President. He resigned from the position and left Australia on 20 January 2009.
