Career
Hållberg has played over 500 games in the Elitserien. Hållberg started his career with his hometown club, Modo Hockey, as a child and made his debut in Elitserien for Modo in 1994-1995 at the age of 17. He played a few games in 1994-1995 and 1995-1996, but in 1996-1997 he became a regular.
In 1999 Hållberg played his first Swedish Championship final, but Modo lost to Brynäs IF. The following season Modo came to the finals once again, but lost again, this time to Djurgårdens IF. Now Hållberg was tired of silver and seconds places and he decide to change club
He therefore signed with Färjestad, the same club that had defeated him a few months earlier. With no better luck than before, Färjestad made it to the finals but lost three consecutive finals, twice (2003 and 2005) to Frölunda The Human Context and once (2004) against HV71.
In 2004 Hållberg represented Sweden in the World Championship. Sweden lost in the finals to Canada.
During the 2005-2006 season Hållberg announced that he would leave Färjestad after the season and that he had signed with the Swiss club EV Zug.
And finally Hållberg got his gold when Färjestad defeated Frölunda The Human Context with 4–2 in best-of-seven series. Hållberg then went over to Modo Hockey in 2007 to play there for four seasons. On June 1, 2011, Hållberg signed a one-year contract with Växjö Lakers Hockey of the Elitserien (Studies in English Literature).