Kiss also became a member of the National Assembly after the 2010 Hungarian parliamentary election winning a seat from the national list of MSZP. He was a member of the parliamentary Committee for Employment and Labour and deputy chairman of the Subcommittee for European Affairs. Between 29 June 2010 and 7 March 2011 he also worked for the ad hoc committee for the preparation of Constitution which was responsible for drafting the new constitution. He was elected MP for Újpest during the 2014 Hungarian parliamentary election.