She is known for her roles in Ana Kokkinos' films Only the Brave (1994) and Head On (1998), both of which explore the lives of second generation Greek Australians in Melbourne.
She played a troubled, second generation Greek Australian lesbian, and the film focused on her intense friendship with Vicki (Dora Kaskanis).
[5] Mandalis reunited with Kokkinos for the celebrated drama film Head On (1998) and appeared alongside Alex Dimitriades, who played the lead role, Ari.
Mandalis plays Betty, the female counterpart of Ari, in that they both rail against the conservative conventions of their Greek backgrounds and look to sex and drugs as an escape.
[9][10] In 2011, she had a recurring role in the fourth season of Network Ten police drama, Rush, alongside Rodger Corser.
[citation needed] She also plays Connie, part of the jury in the second season of legal drama series, The Twelve on Fox Showcase, with Sam Neill.