Csokas made his acting debut in the New Zealand drama series Shark in the Park as Terry Mercer. He appeared in one episode titled "Technical K.O.". For two years (from 1993 until 1995), he portrayed Leonard Rossi-Dodds in the soap opera Shortland Street. In 1996, he starred in the romantic drama film Broken English. From 1997 to 2001, he maintained a recurring role in Xena: Warrior Princess, portraying the character of Borias. Csokas portrayed Lord Celeborn in The Lord of the Rings: The Fellowship of the Ring (2001) and The Lord of the Rings: The Return of the King (2003). Csokas also played the villain Yorgi in XXX (2002), Mr. Smith in Kangaroo Jack (2003), Jarda in The Bourne Supremacy (2004), Trevor Goodchild in Æon Flux (2005), and Guy de Lusignan in Kingdom of Heaven (2005).