Růžička was twice named the top player in the Czechoslovak Elite League, and was on the gold medal team in the Ice Hockey World Championship in 1985 and 1998 Olympic Games.

Since 2008, Růžička has been the head coach of both HC Slavia Praha and the Czech national ice hockey team.

Růžička started his career with Czechoslovak side Litvínov, making his first appearance at the age of 16 and scoring after just 10 seconds in his first game, against Dukla Jihlava.

[2] Růžička had a short career in the NHL, playing a total of five seasons for the Edmonton Oilers, Boston Bruins and Ottawa Senators.

[2] After retiring as a player in 2000 he started working as a coach in HC Slavia Praha and in 2002–03 and 2007–08 seasons his team won the Czech Extraliga.