Played professional soccer for Greece and Australia until he suffered stress fractures to his shins. He also boxes and trained with his brother, Louis Mandylor, in Thai kickboxing.
Australian-born and of Greek descent, Costas and his brother, actor Louis Mandylor are the sons of Yannis and Louise Theodosopoulos. When they got into acting, the brothers changed their surname to "Mandylor", a variation of their mother's maiden name ("Mandylaris"). The two shared the screen as homicidal ghost siblings in Saving Private Leo (2002).
Chosen by People magazine as one of the 50 Most Beautiful People
in the world. (1991)
Resides in Pasadena, California, with his wife Victoria, daughter Athena, and dog Lucas. (2019)
Moved to Los Angeles in 1987.
Made the cover of In Fashion magazine in July 1991, along with Mädchen Amick.
Mandylor and Lauren Holly co-starred twice, first in Picket Fences and again in Just Desserts.