At 16 years old she started working as a model, and in 1993 she made her acting debut in the comedy film Women Don"t Want To. In 2001 she also debuted as a presenter, hosting the La7 game show Zengi. Alexander"s breakout role came in 2003, with the villain Lucrezia Van Necker in the Canale 5 television-series Elisa di Rivombrosa, a role she reprised in the 2007 sequel Louisiana figlia di Elisa – Ritorno a Rivombrosa.
She later appeared in other successful television-series, notably Ho sposato un calciatore, Anna e i cinque and Il commissario Manara.
Since 2011 Alexander hosts the Italia 1 show Mistero.