Ronan made her acting debut in 2003 on the Irish medical drama series "The Clinic" and had her breakthrough in the role of a precocious teenager in Joe Wright's "Atonement" (2007), which earned her a nomination for the Academy Award for Best Supporting Actress. She followed this with starring roles of a murdered girl seeking closure in Peter Jackson's "The Lovely Bones" (2009) and a teenage assassin in "Hanna" (2011), and the supporting role of a baker in Wes Anderson's "The Grand Budapest Hotel" (2014). She garnered critical acclaim for playing a homesick Irish immigrant in 1950s New York in "Brooklyn" (2015), the eponymous high school senior in Greta Gerwig's "Lady Bird" (2017), and Jo March in Gerwig's "Little Women" (2019). She was nominated for the Academy Award for Best Actress for all three performances, and won a Golden Globe Award for Best Actress for "Lady Bird".