Mérő began playing Go when he was 14. He is the son of Hungarian mathematician László Mérő. By 1996 he had already won the European Youth Go Championship and Hungarian Championship. After he finished secondary school he moved to Japan in 1999. He was an insei there for two and a half years. His teacher was Chizu Kobayashi. He was given the chance to study with some of Japan's top players including Satoru Kobayashi and Cho U. After he failed the professional test, he moved back to Europe in 2001. After returning to Europe, a French summer Go camp invited Csaba to become an instructor for the summer. With his experience in Japan as an insei, Csaba came back much stronger and quickly rose to the top of the European standings. He studied sociology at ELTE university in Budapest between 2002 and 2007. He was the president of the Hungarian Go Association between 2006 and 2008.