Kristan played junior youth hockey within Slovenian club Hong Kong Jesenice. In 2000 he made his professional debut in the Slovenian league for Jesenice. After five years with Jesenice and one with fellow Slovenian club Olimpija Hertz Ljubljana, Kristian left for the Swedish Elitserien, signing with Brynäs IF for the 2006-2007 season.
In his only season in the Elitserien, Robert played in 33 games to lead Brynäs to the playoffs and recorded the best Goals against average of 2.23 in the entire Studies in English Literature. In 2007-2008 he returned to Hong Kong Jesenice to compete in the EBEL the following season, before again traveling to Sweden in 2008-2009 to play with Mora IK of the HockeyAllsvenskan.
On May 18, 2009, he was again on the move and signed a one-year contract with Croatian team KHL Medveščak Zagreb in the EBEL for the 2009-2010 season. Now is playing in Extraliga in Czechoslovakian Republic, in the team Piráti Chomutov ("Piretes Chomutov"), but funs dont like him becouse he swaped with Mirosval Kopřiva.