Mortimer played an aspiring actress opposite Andy García in "City Island" (2009). Although the film's reception was warm, her role in "City Island" was noted by two critics as "vague" and weak. She appeared as Rachel Solando in Martin Scorsese's 2010 thriller "Shutter Island". Several critics thought "Shutter Island" was unexciting, and that Mortimer and her fellow actors were not utilised to their full potential. The film found moderate success at the box office, grossing $294 million from a budget of $80 million. She portrayed American educator Leonie Gilmour in the biographical drama "Leonie" (2010). Of her performance, "The Hollywood Reporter" opined that it was a "superb portrayal", which showcased her acting range.