Jeisa grew up in Muçum, Brazil, born to parents Ernani and Ivone of Italian and German blood. She has two sisters, namely Grace (6 years older) and Jessica (5 years younger). She was discovered in 1998 at the age of 13 by a Brazilian actor and was promptly presented to a local modelling agency.

Only a year after first gracing the covers of local magazines was Jeisa signed to the prestigious IMG Models in New York, appearing in Italian editions of ELLE and Marie Claire. The year 2000 brought many fashion campaigns, both local and international, seeing the Brazilian teen in campaigns such as Emanuel Ungaro. Though it wasn't until July 2005 that Jeisa got her big break, adorning French Vogue's cover and well establishing her within the industry.

Jeisa has now starred on the covers of at least five different editions of Vogue (Brazilian, French, German, Japanese and Russian) and has become one of the most successful contemporary runway models. As of 2006, Jeisa, still only 21 years old after 8 years as a fashion model, features in campaigns for Calvin Klein, Roberto Cavalli, Dolce & Gabbana, Hugo Boss, Hermès, H&M, Victoria's Secret and Paul & Joe, as well as in editorials in i-D magazine, Japanese Vogue and L'Uomo Vogue.