In 2004, Massafera won the Miss Paraná Beauty pageant contest, and represented the state in that year's Miss Brasil contest. She finished third, which earned her the title of "Miss Brasil Internacional", and gave her entry into the Miss International contest, held annually in the China. In the international pageant, Grazi (as she is commonly known) did not reach the semi-finals.
In 2005, she took part in the fifth season of the Brazilian version of the reality show Big Brother, known as Big Brother Brasil (BBB). The season was the most-watched season ever. Grazi ended in second, with 40% of the votes.
She started acting classes at Globo acting department. Her first starring role was Renato Aragao 2005 movie: Didi, o Caçador de Tesouros. Renato Aragão (Didi) releases a family movie annually.
At the beginning of 2006 it was revealed that Massafera would get a part in Manuel Carlos next soap, which was an important deal since his soaps are usually the most-watched shows in the country. Initially, she only had a small role on the Rede Globo soap opera, Páginas da Vida, which during its airing was the #1 show on Brazilian television, achieving record ratings. However, due to her popularity, her part was expanded, and eventually became one of the main characters of the soap. Her acting was acclaimed by the press and the public alike and she became one of the biggest celebrities in the country. For her acting, she received a Prêmio Contigo as best newcomer and a Prêmio de Imprensa as personality of the year.
