Dr Clarke qualified from University College Dublin in 1980. He trained in cardiology initially at the Mater Hospital. He then moved to the Royal Postgraduate Medical School at the Hammersmith Hospital where he completed both his MD and PhD theses.
This was followed by a postdoctoral fellowship at Stanford University in California. Dr Clarke returned to Ireland in 1993 when he founded his practice. He moved the clinic to Eagle Lodge in 1995.