Born in Aylesbury, Buckinghamshire, he was brought up in Hertfordshire. Dimsdale is the son of aSwiss mother. He has a sister, Anna. He developed a stammer at age six which he has since partially brought under control through speech therapy. Dimsdale attended the Dragon School and then Eton College, and went on to study French and Economics at university. He trained atGuildhall School of Music and Drama, graduating in 1999. Dimsdale began his performing career at the age of thirteen in a radio play for the BBC. He has lent his voice to the radio productions In The Company of Men and Sharp Focus. His film credits include RocknRolla (2008), Cosi (2010) and the short film Pest. On television, he played the lead roles of Louis Trevelyan in the 2004 adaptation of He Knew He Was Right, and Dr Felix Quinn in the 2008 ITV1 medical drama Harley Street. He has also made guest appearances in Doctors, Casualty and Lark Rise to Candleford. Dimsdale is the co-founder and co-Artistic Director of Filter Theatre. His theatre work includes Great Expectations, The Changeling, Five Finger Exercise and The Tempest. Dimsdale married actress Zoe Tapper on 30 December 2008. In April 2011, she gave birth to their daughter, Ava. Dimsdale won Best Fringe Performer in the 2002 Manchester Evening News Theatre Awards, for theRoyal Exchange performance of Paul Herzberg’s The Dead Wait.