Ján Mucha started his career in his local club TJ Slovan Belá nad Cirochou. Then he moved to MŠK Snina, and later to Inter Bratislava. He spent 2 seasons there, but he didn't play in any match. He moved to MŠK Žilina in summer 2002. He signed for Legia Warszawa in Poland in summer 2005. He won the Slovak championship there twice. In 2005, he was sent on a half-year loan to HFC Humenné.
He signed for Legia Warszawa in Poland in summer 2005. With Legia he has won the 2007-08 Polish Cup and the Polish Supercup in 2008. In January 2010 Mucha signed a pre-contract deal with Everton to join in July the same year.
Jan made his International debut for Slovakia in February 2008, in a friendly match against Hungary. At the time of signing for Everton, Jan had played 14 times for his country and was looking forward to playing in the World Cup in South Africa.
