He was interested in acting as a child, then at the age of 19, after a stint in the Territorial Army, O'Kane left the country.
He took on stunt work, modeling and acting in student films, and arrived in Hollywood in the early 1980s.
When the cast and crew discovered his young age, and the fact that he lived in the parking lot in a truck, they took him under their wings, and O'Kane appeared in several episodes over three years, although having a thick Glasgow accent impeded his chances of speaking on the show.
After laying down The Prime of Miss Jean Brodie on tape at the request of Tyne Daly, in return she encouraged the young actor to learn more accents to broaden his talents.
O'Kane landed his first leading role in the British TV game show Interceptor (1989).