Cassells was born in Airdrie, Scotland where he started his career as a keyboard player in a local band. Having moved to Bournemouth in 1978 he became a full time Entertainer and worked for 25 years on cabaret circuit all over the UK and Abroad. Working in summer season in the Bournemouth Holiday circuit kept him very busy.
Cassell's decided he wanted to train in all aspect of the Performing arts therefore he soon found himself training at Weymouth college in all aspects of the theatre and got involved in productions including 'Hiawatha', 'The Miser', 'Chicago' and 'Our Country's Good'. At that time he also appeared in 'Jamaica Inn' at the Towngate Theatre in Poole and in 'West Side Story' at the Winter Gardens Theatre in Bournemouth with the famous 'Big Little Theatre Company'. He also gained his Bronze, Silver and Gold medals for acting from the London Academy of Music and Drama.
Cassells has appeared in several television productions such as 'The Ruth Rendall Mysteries', 'Trainer', 'Howard's Way', 'Eastenders', 'Casualty', 'Dr. Who' and the comedy 'Waiting For God'. In 1997 he was the subject in the first episode of the series 'All The World's A Stage' produced by West Country Television. The documentary focussed on Cassells' career in Entertainment with an in depth interview and a look behind the scenes.
By 1999 Cassells cabaret show, 'Mr Ken Dee and Company', was now experiencing tremendous success and had been running for 12 years. Throughout this time the show had toured the UK, the Edinburgh Festival and had appeared at many major functions, the most notable being at The Conservative Party Conference.
In 1999 Cassells decided to return to Weymouth College to study further and gained his 'HND' in Performing Arts. Here he started to shine as an accomplished actor playing the demanding role of the serial killer Reginald Christie in 'Christie In Love'. In the mystery play, 'The Fall And Of Redemption Of Man' Cassells played four roles simultaneously. In 2002 Cassells gained a 'BA Honours Degree' in 'Theatre And Performance With Music' at Plymouth University.
Cassells then attended the 'London Academy Of Performing Arts' studying a post-graduate course in classical acting with music. He has appeared in Shakespeare's 'Twelfth Night', playing Olivia, and in 'Hamlet' playing Claudius. He has also appeared in Chekov's 'Three Sisters', 'The Proposal', 'Uncle Vanya' and 'The Seagull' and in Molière's 'The Misanthrope' and 'The Miser'.
When Cassells finished Drama School he started performing under the name of Kenneth MacDonald only to find out two years later that Kenneth Macdonald was an actor who died in 2003! Just before he finished Drama school in 2008 Ken changed his name to Cassells and has now started the arduous task of networking his new name.
Cassells is working as a full time drama coach and Teacher and while working in full time education, Cassells has Directed many plays and musicals to include Grease, Chicago, Musicals in Concert, The Beaux Stratagem, and Musical Director for Sweet Charity.