Prior to moving into the host position in the fall of 2012, Martin started as National Security Correspondent for NPR in May 2010. In that position she covered both defense and intelligence issues. She traveled regularly to Iraq and Afghanistan with the Secretary of Defense, reporting on the US wars and the effectiveness of the Pentagon's counterinsurgency strategy. Martin also reported extensively on the changing demographic of the US military – from the debate over whether to allow women to fight in combat units – to the repeal of Don't Ask Don't Tell. Her reporting on how the military is changing also took her to a US Air Force base in New Mexico where the military for a rare look at how the military trains drone pilots.
Martin was part of the team that launched NPR's experimental morning news show, The Bryant Park Project, based in New York — a two-hour daily multimedia program that she co-hosted with Alison Stewart and Mike Pesca.