Keith trained as an actor at London's renowned Arts Educational School, and as a fight director under the late John Waller, with whom he co-authored the book “Sword Fighting: A Manual for Actors and Directors”.

In 1995, he joined the creative team of Britain's award-winning Royal Armouries Museum, playing a major role in spearheading its revolutionary Live Interpretation initiative. Nearly a quarter of a century later, he continues to delight the Museum’s visitors by giving explanations and demonstrations of historical weaponry and fighting techniques.

Keith is a member of British Actors Equity, the Screen Actors Guild and the American Federation of Television and Radio Artists.