Played professional soccer in Australia from age 16 to 20.

The son of Yannis and Louise Theodosopoulos and brother of actor Costas Mandylor. The two shared the screen as homicidal ghost siblings in the fourth season episode Saving Private Leo (2002) of Charmed (1998). Australian-born of Greek descent, "Mandylor" is a variant of their mother Louise's maiden name, Mandylaris.

Was one of the finalists to play Joey on Friends (1994) before Matt LeBlanc won the role. Mandylor later appeared on the show as Joey's doppelgänger Carl in The One with Unagi (2000).

Expert in muay thai (Thai kickboxing).

Produced and co-wrote his first short film (My Brother Cicero (1998)) in which he and Costas Mandylor (his brother) starred.