He started out as a
winger, but during his time at
Norwegian club
Molde was changed into a defender. He is known for his forward runs and good heading, given his tall frame. However, he is also known for making occasional blunders in the national team as he has been forced to play out of his preferred position. Before joining Molde he played for
FC Jazz,
TPV Tampere and
HJK Helsinki in Finland's
Veikkausliiga. He won the
Norwegian Cup in 2005. In 2007, he briefly went on trial at
Lokomotiv Moscow and played 3 times. In 2007, he moved to
Young Boys in Switzerland. On 31 January 2008, Kallio joined Fulham on loan, together with
Jari Litmanen. He made his Fulham debut the following season against
Arsenal, in which he helped secure a 1–0 victory. He was immediately awarded the Man of the Match award by visitors of the
BBC website. On 3 July 2008, Kallio signed a two-year deal with Fulham. Kallio joined
Sheffield United on a one-month loan deal in late November 2009, making his debut just over a week later at
Plymouth. After making two appearances, Sheffield United extended his loan deal until the end of January 2010 but just hours after
Roy Hodgson recalled Kallio due to injuries in defence. On 1 February 2010, Kallio once again joined the Blades on loan until the end of the season. On 1 July 2010, Fulham announced that Kallio had been released from his contract with Fulham. After being released by Fulham, Kallio joined Norway's
Tippeligaen side
Viking for the rest of the
2010 season. But after making only one appearance as a substitute for the club, the 32-year-old defender was released from his contract on 16 November 2010. Kallio signed a contract at the beginning of year 2011 with
Thai Premier League side
Muangthong United F.C. which won the Premier League title on season 2010. On 19 May 2011
Muangthong United F.C. has been terminated contract. Kallio joined
Finnish Premier League side
FC Inter Turku on 8 June 2011. On 18 January 2012 it was announced that he would join
Ilves in Finnish second division. Kallio announced his retirement on 3 October 2013. ==Coaching career==