Antonelli was born on March 18, 1976, in Rio de Janeiro. She is the daughter of Hilton Prado and dancer Suelly Antonelli. She also has one older brother, Leonard.
Giovanna started her career when she was 14. Her artistic career began on the children's program Angélica of the Rede Manchete. She was an "Angelicat" (the assistant of Angélica). Her early works include television series Tropicaliente, Tocaia Grande, Xica da Silva, Corpo Dourado, Força de um Desejo and Você Decide.
Antonelli got her first important role in Malhação. She portrayed Isa Pasqualete from 1995 to 2000. In 2000, she portrayed Sharon in 2000 film Bossa Nova.
After her film debut, she got the role of Capitu in 2000 telenovela Laços de Família. She says that those girls, just like Capitu, are very smart. They receive a good education and they escort their customers to important lunches, dinners; sex is not always the most important part of the encounter. After that role, Giovanna has played Mary Magdalene in the theater show Jesus Christ Superstar.
In 2001, she portrayed Jade on O Clone, and her co-star was Murilo Benício. The big success of this multicultural telenovela was enormous, and Giovanna traveled a lot to promote it together with Benício. The role of young Muslim girl Jade in O Clone was very demanding for her, she practiced belly dancing 6 hours a day for 2 months so that when she danced it would look like she has it in her blood. It is an obstacle for them to marry because her uncle Ali does not allow her to marry a Christian. She is forced to marry Said other Muslim guy. But at the end she gets back with Lucas. In 2002, she acted in the movie Avassaladoras. A year later, Giovanna played the role of Brazilian heroine from Santa Catarina, Anita Ana Garibaldi, in mini-series A Casa das Sete Mulheres. That role was very important for her and once again she worked with director Jayme Monjardim, and many great actors like Thiago Lacerda, Dalton Vigh, Daniela Escobar, Camila Morgado and Werner Schünemann. For four months, while acting Anita Garibaldi, Giovanna patiently read Anita's biographies and practically lived her life. After the shooting ended, Giovanna said that she was glad that she can have a haircut and see herself with a new, modern haircut, the long black hair bored her.
Also, in 2003, Antonelli portrayed Virgin Mary in the film Maria, Mãe do Filho de Deus. A year later, she acted in the film A Cartomante. She also returned to telenovelas, portraying in the telenovela Da Cor do Pecado.
In 2006, she portrayed Bia in the series Minha Nada Mole Vida. In 2007, she portrayed in mini-series Amazônia: De Galvez a Chico Mendes and the film Caixa Dois. From 2007 to 2008, she portrayed Clarice in telenovela Sete Pecados.
In 2009, two new films portraying Giovanna Antonelli will be released - The Heartbreaker and Budapest.
Giovanna is very close with her family. Her father, Hilton Prado, is a former opera singer, her mother, Suely Antonelli, is a former ballet dancer, and brother Leonardo is a lawyer.
In 1997 Antonelli was married to publicist Ricardo Medina, whom she had known since high school. The couple divorced on December 2001. In 2002 Giovanna Antonelli began dating O Clone co-star Murilo Benicio. On December 2004, Giovanna had a car accident which she blamed on the paparazzi who followed her everywhere. At a press conference which she held after getting out of the hospital, she, along with boyfriend Murilo Benício, admitted that she was a few months pregnant. The news was very well received by her fans all around the world and on May 24, 2005 she gave a birth to her first child, a boy named Pietro, in Rio de Janeiro. Antonelli and Benicio broke up on 2007 after a 5-year relationship.
Currently, she's married to director Leonardo Nogueira with whom she has twin girls, Antonia and Sophia, born on 8 October 2010.