Paquin was born July 24, 1982 in Winnipeg, Manitoba, Canada, the daughter of Mary Paquin (née Brophy), an English teacher and native of Wellington, New Zealand, and Brian Paquin, a high school physical education teacher. Paquin is the youngest of three children; she has two older siblings: brother Andrew, born in 1977, and sister Katya, born in 1980. Paquin moved to New Zealand when she was four. She attended the Raphael House Rudolf Steiner School until she was eight or nine. Her musical childhood hobbies in New Zealand included playing the viola, cello and piano. She also did gymnastics, ballet, swimming and downhill skiing, though she did not have any hobbies related to acting.
While in New Zealand, Paquin attended Hutt Intermediate School in 1994 and 1995, where she completed Form 1 and 2. Having begun her secondary education in Wellington at Wellington Girls' College, she completed her high school diploma at Windward School in Los Angeles, where she moved with her mother following her parents' divorce in 1995. She graduated from Windward School in June 2000 and completed the school's community service requirement by working in an LA soup kitchen and at a special education center. She studied at Columbia University for one year, but has since been on a leave of absence to continue her acting career.
It was in New Zealand in 1991 that Paquin became an actress by chance. Director Jane Campion was looking for a little girl to play a key role in The Piano, set to film in New Zealand, and a newspaper advertisement was run announcing an open audition. Paquin's sister read the ad and went to try out with a friend; Paquin herself tagged along because she had nothing better to do. When Campion met Paquin—whose only acting experience had been as a skunk in a school play—she was very impressed with the nine-year-old's performance of the monologue about Flora's father, and she was chosen from among the 5000 candidates.
When The Piano was released in 1993 it was lauded by critics, won prizes at a number of film festivals, and eventually became a popular movie among a wide audience. Paquin's debut performance in the film earned her an Academy Award for Best Supporting Actress at the age of eleven, making her the second-youngest Oscar winner in history after Tatum O'Neal. The Piano was made as a small independent movie and wasn't intended to be widely known, and Paquin and her family didn't plan to continue in the acting circles. However, she was invited to the William Morris Agency, and she kept receiving offers for new roles. She systematically refused them, but she did appear in three commercials for the phone company MCI (now Verizon). She also appeared as a voice in an audio book entitled The Magnificent Nose in 1994.
In 1996, she appeared in two movies. The first role was as young Jane in Jane Eyre. The other was a lead part in Fly Away Home playing a young girl who, after her mother dies, moves in with her father and finds solace in taking care of orphaned goslings.
In the summer of 2006, she completed filming Blue State. She was the executive-producer of the film, the film having been made by Paquin Films, a production company formed by both her and her brother, Andrew Paquin. In November 2006, she completed Margaret. This film has yet to be released. Its release is unknown, due to ongoing legal disputes.
In 2007, Paquin received an Emmy Award nomination for Supporting Actress In A Miniseries Or A Movie for her role as Elaine Goodale in HBO's made-for-TV movie Bury My Heart at Wounded Knee, based on Dee Brown's bestseller. She also received Golden Globe and Screen Actors Guild Award nominations in similar categories.
In 2008, Paquin appeared as Sookie Stackhouse in the HBO series True Blood, her first role in a TV series. The show is based on The Southern Vampire Mysteries series of novels by Charlaine Harris. Paquin won a Golden Globe for Best Actress in a Television Drama Series for her role in the show, and also won a Satellite Award in a similar category. The second season of the show began airing in the US on June 14, 2009.
In 2009, Paquin played Irena Sendler, a Polish woman hailed as a heroine of the Holocaust, in The Courageous Heart of Irena Sendler, a CBS TV film biopic based on the book Mother of the Children of the Holocaust: The Irena Sendler Story,
by Anna Mieszkowska. The film was made in Latvia, and was a Hallmark Hall of Fame presentation for the network.
Paquin is also an award-winning stage actress, having made her stage debut in 2001 in a production of The Glory of Living at the MCC Theater. She won a 2001-2002 Theater World Award for her performance. She has since appeared in a number of other plays, but has only once appeared in a play outside of the USA, when she appeared on the West End stage in London in a production of This is Our Youth in 2002.
On August 5, 2009, it was announced that Anna Paquin had become engaged to her True Blood co-star Stephen Moyer, whom she had been dating since filming the series' pilot in 2007. Paquin lives in Venice, Los Angeles, California. Her hobbies include surfing and cycling.