Her debut album Alas, I Cannot Swim was released on 4 February 2008, and was nominated for the 2008 Mercury Prize. The album, as well as subsequent singles, were released on Virgin Records. The third and final single from her album, "Night Terror" was released on 27 October 2008, coinciding with a 6-date "Night Terror tour".
Marling's television appearances include The Late Late Show with Craig Ferguson and Later With Jools Holland, performing "Ghosts" and "New Romantic" respectively. In 2008, she appeared on Russell Brand's Radio 2 show alongside her sister. She once chose to perform on the street after being denied entry to one of her own performances for being underage.
Marling dated Noah and the Whale singer/guitarist Charlie Fink briefly before the pair separated in 2008. She also dated Marcus Mumford of Mumford & Sons until late 2010. She moved to Silver Lake in Los Angeles, California in 2013, before relocating to London in December 2014.