Unterluggauer began his career with EC VSV in 1992. After two years in the Western Hockey League with the Brandon Wheat Kings, he returned to Villach, where he stayed until 2001, year where he tried his luck in Germany with the Schwenningen Wild Wings of the Deutsche Eshockey Liga (DEL). After a single season in Schwenningen, he moved to the DEG Metro Stars until 2005. That year, he came back to his homeland, joining HC Tiroler Wasserkraft Innsbruck. With the team's financial problems in 2009 and its voluntary demotion to the Austrian Nationalliga, Gerhard Unterluggauer found himself forced to leave the team - he joined VSV EC. A fairly offensive defenceman, Unterluggauer collected a total of 137 goals and 286 assists (423 points) in 755 career games, all competitions together.
Unterluggauer is a regular member of the Austrian National Team. The reliable defenceman has played in 12 World Championships and in one olympic tournament, in 2002. He also took part in three World Junior Championships, and managed to finish the 1994 World Junior Championship B as the tournament's most penalized player.