Viktor Kassai was born on the 10th September 1975, in Budapest. He took his refereeing badge in 1990, and then began to work his way up the county leagues, during the years 1990-1995. His first game was as an assistant ref for the Szarliget-Obarok fixture in 1991. His first senior game was back on the 11th April 1993, when Aszar played Csaszar. The next step was division 3, during the years 1995-1997. The following season saw him move up to referee second division games.

FIrst division matches followed from 1999, with his first game being on the 20th March 1999, in a game involving Zalaegerszeg and BVSC. Kassai also officiated in several World Cup 2010 games, this summer in South Africa. His last game with Vidi happened last season, in the 2-2 away draw at ZTE.