Dermott is a member of the Irish showjumping team, a former Individual World Showjumping Champion and a European Team Champion. Dermott partnered a very successful mare, Liscalgot, and the pair were part of Irish teams that won a record of ten FEI Nations Cups from 1999 to 2000.
In 2002, he recorded an Individual Gold Medal in the Showjumping World Championships, riding Liscalgot to victory again. This was Ireland’s first-ever win at the World Championship.
Dermott has been a member of numerous Nations Cup Teams and has represented Ireland on many occasions, including in 2013, as he helped Ireland claim third prize in the Aga Khan.