Konstantin "Costa" Ronin (Russian: Константин "Коста" Ронин; born 3 February 1979) is a Russian and Australian actor and cinematographer, best known for appearances in Red Dog, as Gregorovich on the SBS drama East West 101, as Oleg Igorevich Burov in the FX drama The Americans and as Yevgeny Gromov on Homeland.

Ronin was born in Kaliningrad, Russian SFSR, Soviet Union (now Russia).^[1] He spent the first 17 years of his life in Russia.^[2] In his youth, he moved to Wellington, New Zealand with his mother and studied international relations and political science at Victoria University, before moving to Perth, Australia for further tertiary education^[1] and, later, to Sydney.^[3][4]

At age 15, Ronin commenced working and learned about American culture at a radio station that taught English through music.^[3]

Growing up in Kaliningrad, Ronin was taught to sail by his father and grandfather at age five and remains passionate about it.^[3]

He married Leah Lowder in June 2021. They live in New York,^[1][5] having previously lived in Los Angeles, Surry Hills and Sydney.^[6] His grandmother lives in Australia.^[1]