Fadden spent his career as a civil servant, beginning in 1978 as a Foreign Service Officer in the Department of External Affairs. He moved to the Security and Intelligence Secretariat of the Privy Council Office in 1983. Subsequently, he was Principal Officer with the Auditor General from 1988 and was promoted to legal advisor and assistant Auditor General in the Office of the Auditor General of Canada from 1990 to 1996. Other postings included:
Fadden served as Director of the Canadian Security Intelligence Service from June 2009, when he replaced Jim Judd, until his abrupt resignation in mid-May 2013. Fadden made headlines in June 2010 by announcing that foreign countries were both performing industrial esponiage against Canada, and trying to influence Canadian politicians. Fadden went on to say that Cabinet Ministers in two provinces, and several municipal politicians, were influenced by a foreign government when making policy decisions. Several others have criticized Fadden for his remarks, especially since they were in a CBC National interview released just before the G8 and G20 summits in Ontario; the interview was conducted earlier in the year, after the CBC approached Fadden to repeat statements he had made in a private speech at the Royal Canadian Military Institute. Although no countries were named, the National Post, Globe and Mail, CBC, CTV, and several other Canadian media outlets have speculated that Fadden is referring to China. In April 2013, it was announced that Fadden would step down from his position on May 13 to become Deputy Minister of National Defence. Deputy Director of OperationsMichel Coulombe was designated as Fadden's replacement, in an interim role until a new director is appointed.
Fadden was appointed National Security Adviser in early 2015 by Stephen Harper. As national security and intelligence adviser, Fadden's "insistence that foreign powers, notably the Chinese Communist Party, had cultivated agents of influence at various levels of government in Canada" hurt his standing with the Liberal Party of Canada, which became the governing party of Canada in late 2015. Fadden was replaced by Daniel Jean, who lacked experience in either national security or intelligence. Fadden's concerns have since been borne out by a series of revelations, including a Financial Times investigation that cast light on "an internal document prepared by the overseas section of Beijing’s United Front Works Department" that showed how China was influencing electoral politics in foreign countries. Fadden was quoted as saying “What we’re seeing in Australia and New Zealand, I’ve seen no suggestion that not trying to do the same thing in every other country in the west, Canada included. Their intelligence organizations are fairly active here,” Fadden said. “I refuse to believe they’re not trying to the same thing in France, the U.K. and Germany. It’s just how they try to exert their influence. I’ve seen nothing to suggest we’re insulated from what we’re seeing in Australia and New Zealand."
