Berg starred for the junior and senior clubs in his hometown and caught the attention of many pro scouts with his size, mobility and hard low shot from the point. He was one of the top-rated players prior to the 1995 NHL Entry Draft and was the third player taken when his name was called by the Kings.
Berg was eased into the L.A. lineup over the next three seasons but was never able to elevate himself above the responsibilities of a fifth or sixth defenceman. He was chosen to play for Finland at the 1998 Nagano Olympics and helped his country capture the bronze medal.
The Kings gave up on the young Finn in March 2001 and dealt the former first rounder to the Toronto Maple Leafs. Upon his arrival with the Maple Leafs, Berg scored three goals in 12 games and was solid during eleven post-season games.
Over the course of the next three seasons, Berg kept his game simple and his durability became an asset to the Toronto blueline. During the 2003-04 season, Berg reached the 500-games played plateau, and the following year returned to Europe to compete with Timra IK in Sweden during the NHL lockout. As the NHL game returned, so too did Aki Berg on Maple Leaf blue-line. Berg went on to spend another season with the Leafs in 2005-06 and represent his homeland at the 2006 Winter Olympics, capturing a silver medal. Berg returned to Europe in 2006, signing as a free agent with Turku in Finland.
On the international stage, Berg has represented his homeland at the 1997 World Junior Championships, the World Championships (1999-2001, 2003), the World Cup of Hockey (2004) and the Winter Olympics (1998, 2002, 2006).