Goran Višnjic ( ; ; born September 9, 1972) is a Croatian American actor who has appeared in American and British films and television productions. He is best known in the United States for his role as Dr. Luka Kovac on the NBC television series ER. He is the son-in-law of Croatian film director and former head of Croatian Radiotelevision (1991–95), Antun Vrdoljak.