Born in Australia, he was part of an Antipodean acting family that included his father, veteran TV actor Andy McPhee, and his sister, Sianoa Smit-McPhee of "Hung" (HBO, 2009-) fame. After making his stage debut in a 2005 musical theater production of the seminal Australian film "Walkabout" (1971), he appeared in his first big screen effort, the short black comedy "Stranded" (2005), about a hapless family who struggle to function after the matriarch's suicide. A supporting role as a rural influenza victim in the hysteria-driven TV movie "Fatal Contact: Bird Flu in America" (ABC, 2006) followed, in which he was cast because of its New Zealand filming locations. Stateside audiences had more opportunities to view Smit-McPhee's talents that year in "Nightmares & Dreamscapes: From the Stories of Stephen King" (TNT, 2006), a limited-run anthology series built around the horror master's short stories. Smit-McPhee turned up in two episodes: in the noir pastiche "Umney's Last Case," he was the ill-fated son of William H. Macy's crime fiction writer, who hires his own hard-boiled creation to figure out his life, while "The Fifth Quarter" cast him as ex-con Jeremy Sisto's offspring. Like "Fatal Contact," the series was filmed in New Zealand. He also turned up as a younger version of New Zealand actor Kieran Hutchinson's heartthrob lead in the primetime soap, "Monarch Cove" (Lifetime, 2006). In 2007, Smit-McPhee won the highest acting honor for a young actor for his performance in "Romulus, My Father" (2007), an affecting adaptation of philosophy professor Raimond Gaita's difficult early years. He showed keen sensitivity and an emotional range beyond his years as the young Gaita, who struggled to maintain a semblance of order in his life while his parents, played by Eric Bana and Franke Potente, struggled with assimilation and mental problems. Smit-McPhee was showered with critical praise, as well as both the Young Actor's Award from the Australian Film Institute - the Australian equivalent of the Academy Award - but also the Film Critics Circle of Australia's Special Achievement Award.After a supporting role as the boyhood version of Australian actor John Wesley in "The King" (TV1, 2007), a biopic of Graham Kennedy, that country's first television superstar, Smit-McPhee received his first substantial Hollywood role in "The Road." His role, The Boy, an unnamed pre-teen who struggles to survive a post-apocalyptic world with his father (Viggo Mortensen), was crucial to the film's success; if the actor chosen could not believably portray the character as both a normal child before the disaster and a terrified survivor in the years afterwards, the film's central relationship - its emotional core - would have been compromised, causing the whole project to collapse upon itself. An audition tape from Smit-McPhee's father made him a leading contender for the role, which he eventually won thanks to his advanced skills and innocent exterior. The young actor also impressed his established co-stars, which included Oscar winners Charlize Theron and Robert Duvall, with his perseverance under challenging shooting conditions (the film was shot in Pennsylvania during the winter). At one point, Smit-McPhee remained in a freezing stream for numerous takes, despite enduring physical pain. Critics again bestowed rave reviews, with the Broadcast Film Critics Association nominating him for Best Young Actor.After returning to his native country for "Matching Jack" (2010), a melodrama about a mother (Jacinda Barrett) of a terminally ill boy who becomes attached to his hospital bedmate (Smit-McPhee), the actor was announced as the lead in "Let Me In" (2010), the controversial American remake of the Swedish vampire movie "Let the Right One In" (2008). Smit-McPhee was cast as a young American boy who forms a relationship with a girl (Chloe Moretz) who may be at the center of a string of grisly murders. The film garnered an equal amount of positive and negative responses, with the latter coming largely from fans of the original picture, which viewed a remake as unnecessary.