Demeter Gui was born in Carei (Nagykároly) in the region of Transylvania in Romania in 1949.
He studied arts, drawing and sculpting in his hometown Carei (Nagykároly) and in Cluj (Kolozsvár) at the local high school training artists. After leaving school, he had been dealing with sculpting for long decades, mainly focusing in religious arts. His marble altars and baptising basins can be seen in Catholic churches throughout Transylvania (he planned and sculpted these artistic objects himself).
He settled in Hungary in 2002, where he returned to his original profession, painting.