Saoirse Ronan made her screen debut on Irish public service broadcaster RTÉ, in the 2003 primetime medical drama The Clinic and the 2004–2005 mini-serial Proof. During the same time, she auditioned to play Luna Lovegood in Harry Potter and the Order of the Phoenix, a role she eventually lost out to Evanna Lynch. At the age of twelve, she was asked to attend a casting call for Joe Wright’s 2007 film adaptation of Ian McEwan’s 2001 novel Atonement. She auditioned for and won the part of Briony Tallis, an aspiring 13-year-old novelist, who irrevocably changes the course of several lives when she accuses her older sister’s lover of a crime he did not commit. Starring alongside Keira Knightley and James McAvoy, Wright grew more and more impressed with Saoirse on-set, who declared her role a “fantastic part [to play].” Budgeted at US$30 million, the film became a financial and critical success, resulting in a worldwide box office total of US$130 million and various awards, including the BAFTA Award for Best Film, Golden Globe for Best Motion Picture – Drama, and an 2008 Academy Award nomination for Best Picture.Saoirse herself received rave reviews for her performance, with Ty Burr of the Boston Globe calling her “remarkable [and] eccentric,” and was subsequently nominated for a BAFTA, a Golden Globe and an Academy Award for Best Supporting Actress, ranking her among the youngest persons ever to be nominated for the latter.
Saoirse’s next film was Amy Heckerling’s often-delayed romantic comedy film I Could Never Be Your Woman (2007). Initially shot in mid-to fall 2005 in Los Angeles and London, the film went straight-to-DVD in the United States and other major market territories after it had struggled to attract financing and several deals disintegrated during its post-production in spite of its budget of US$25 million. In the film, Ronan portrayed the character of Izzie Grossman, the pubescent daughter of a television show screenwriter, played by Michelle Pfeiffer, who falls for a younger man (Paul Rudd), while Izzie falls in love for the first time herself. Upon its release, the independent project garnered generally lukewarm reviews, with Joe Leydon of Variety summing it as “a desperately unfunny mix of tepid showbiz satire and formulaic romantic comedy.”
In 2008, Saoirse starred in both Death Defying Acts and City of Ember. In Gillian Armstrong’s supernatural romantic thriller Death Defying Acts, she played Benji McGarvie, the daughter of an impoverished and uneducated psychic, played by Catherine Zeta-Jones, who begins a passionate affair with magician Harry Houdini at the height of his career. She was awarded an Irish Film & Television Award for her performance. Released to a mixed reception, the film was not a success at the box office, barely grossing US$8.3 million worldwide. In Gil Kenan’s City of Ember Ronan starred as Lina Mayfleet, a teenager who must save the people of the fictional underground city named Ember. The fantasy film, based on the 2003 novel by Jeanne DuPrau, received mixed reviews from critics, and grossed US$17 million worldwide, well below its US$55 million budget.
In 2009, Saoirse appeared alongside Rachel Weisz, Mark Wahlberg, Susan Sarandon and Stanley Tucci in Peter Jackson’s The Lovely Bones (2009), an adaptation of the same-titled book by Alice Sebold. In the film, Saoirse plays 14-year-old Susie Salmon, who, after being murdered, watches from the “in-between” as her family and friends struggle to move on with their lives while she comes to terms with her own death. Ronan and her family were originally hesitant for Ronan to accept her role in the film because of its subject matter, but agreed after meeting with Jackson, who described her as “just amazing on-screen.” The Lovely Bones was released to mainly mixed reviews from critics, who criticised the film’s story and its message. Praised for the acting however, particularly Saoirse’s, whose performance Richard Corliss of Time described as “magic,” the film garnered various accolades, winning Ronan a Critics’ Choice Award, a Saturn Award and a second BAFTA Award nomination the following year.
In 2010’s The Way Back, directed by Peter Weir, Saoirse played the character of Irena, a Polish orphan, who joins a group of prisoners who escape from the gulag in Siberia in 1940 and attempt to make a 4,000 mile trek to India. Shot on location in Bulgaria, India and Morocco alongside Jim Sturgess, Colin Farrell and Ed Harris, the war drama film received generally positive reviews, with The Telegraph calling it “a journey that feels awful and heroic and unfathomable – and one you’ll want to watch again.” Her performance in the film garnered Ronan her fourth Irish Film & Television Award.
In 2011, Saoirse starred in the title role of the action thriller film Hanna, which marked her reunion with Atonement director Joe Wright. The film co-starred Cate Blanchett and Eric Bana and earned positive reviews. Saoirse won the Irish Film & Television Award for Best Actress in a Lead Role for her performance in Hanna.
In November 2011, Ronan took part in a promotion for the Irish Film Institute Archive Preservation Fund, in which she was digitally edited into popular Irish films of the past, such as Once and My Left Foot, as well as documentary footage on the arrival of John F. Kennedy at Dublin Airport and the GAA All-Ireland finals. Ronan’s next film was Andrew Niccol’s film adaptation of Stephenie Meyer’s novel The Host in which she plays the dual main characters of Wanderer and Melanie Stryder, a human rebel who was captured and implanted with a parasitic alien soul. Also in 2013, Ronan starred in director Neil Jordan’s vampire film Byzantium, an adaptation of the play of the same name, and in Geoffrey S. Fletcher’s directorial debut Violet & Daisy, where she again played a teen assassin. She was in talks to play the role of wood elf Itaril in Peter Jackson’s The Hobbit but she later stated that she would not be appearing in the film. She said that she was “really disappointed” to have to turn down the role, “but there are other projects as well that I’ve had to consider – and to do [The Hobbit] over a year, it wouldn’t have left me time to do anything else”. Saoirse’s last film in 2013 was the film adaptation of the 2004 novel How I Live Now by Meg Rosoff. In the film, she plays a New York City teenager who is sent to stay with cousins on a remote farm in the United Kingdom during the outbreak of a fictional third world war. Directed by Kevin Macdonald, it was screened in the Special Presentation section at the 2013 Toronto International Film Festival.
In 2014, Ronan appeared in Wes Anderson’s The Grand Budapest Hotel, which co-starred Bill Murray, Ralph Fiennes, Adrien Brody, Jude Law and Owen Wilson; and in Lost River, the directorial debut of Ryan Gosling. In April 2014, Saoirse has been cast as Leia in the psychological thriller Stockholm, Pennsylvania directed by Nikole Beckwith. She was also cast as the lead role, Eilis Lacey, in John Crowley’s film Brooklyn, which is based on the novel of the same name by Colm Toibin.