'The King and I'. In 1949, Yul Brynner made his film debut in Port of New York, co-starring with Scott Brady and Richard Rober. Not long after, he landed his most famous role, playing King Mongkut of Siam in Oscar and Hammerstein's production of The King and I in 1951.ul Brynner-The King and I (TV-14; 1:13) Watch a short video about actor Yul Brynner and discover how he got his most famous role.