He is best known to American audiences for series regulars roles on Chicago P.D., Power Rangers Lost Galaxy as well as long-running hit CSI: Crime Scene Investigation.

While attending George Mason University, Kao joined the Sigma Chi fraternity and graduated with a degree in Speech Communication in 1992.

He has also appeared on TV shows such as Desperate Housewives (as Steve), ER (as Yuri), NBC's Heroes, Century City, Huff (as Kane), Power Rangers Wild Force (as General Venjix), Once and Again (as Steven), L.A.

Kao appeared as Sebastian in Wayne Wang's Snow Flower and the Secret Fan, and starred as the main romantic lead, Jefferson, in Quentin Lee's The People I've Slept With.

Kao has also had roles in films such as The Hills Have Eyes 2 (as Han), Nomad: The Warrior (as Shangrek), When In Rome (as Nobu), and Jet Li's The One (as Woo).

In 2021, Kao starred in the holiday romance film Christmas at the Ranch with Amanda Righetti, Lindsay Wagner, Laur Allen and Dia Frampton playing the character Charles.