McTernan was Prime Minister Tony Blair's Director of Political Operations from 2005 to 2007. He then worked on the November 2007 Australian Labor Party federal election campaign. From 2007 to 2010 he was special adviser to two Cabinet Ministers in Gordon Brown's Labour Government: first to Des Browne, Secretary of State for Scotland and Secretary of State for Defence, and then to Jim Murphy MP, the Secretary of State for Scotland from 2008 until May 2010. From June 2010 to October 2011, he was a columnist at "The Scotsman", and then director of communications for the Australian Labor prime minister, Julia Gillard, from September 2011 to June 2013.