In 2008 Leonard played the female lead in the BBC remake of The 39 Steps. Part of the Christmas scheduling, its first showing was the most watched programme on BBC One on that day. Leonard starred as Cynthia in Joanna Hogg's 2010 feature film Archipelago. In 2012, Leonard starred in two episodes of ITV drama series Whitechapel, as Psychiatrist Morgan Lamb, for which she was nominated for Most Outstanding Actress at the Monte Carlo television awards. In 2013 Leonard played a leading role in the action adventure film Legendary: Tomb of the Dragon alongside Dolph Lundgen and Scott Adkins. In 2013 Leonard played Alex Lang in DreamWorks The Fifth Estate starring Benedict Cumberbatch. In 2015, Leonard played Virginia Woolf in Life in Squares, a BBC miniseries on the Bloomsbury Group.