Career
Severin played for Heart of Midlothian, Aberdeen, Watford, Kilmarnock and Dundee United. Severin was club captain of Aberdeen for two seasons. He also made 15 appearances for the Scotland national football team
During his career, Severin played as a defensive midfielder, centre back, right back, striker, and once as a goalkeeper for Hearts.
Severin started his career at Heart of Midlothian. Severin started to play regularly for Hearts in the 1999–2000 season, making 28 appearances in all competitions and scoring his first professional goal in a Scottish League Cup match against Queen of the South.
Severin played once as a goalkeeper for Hearts, following an injury to Teuvo Moilanen. In July 2004, Severin left Hearts on the expiration of his contract, and became Jimmy Calderwood"s first signing at Aberdeen.
He signed a new three-and-a-half year contract with Aberdeen in December 2005.
In July 2007 he was handed the captaincy of Aberdeen, succeeding Russell Anderson. In June 2009 the Watford Observer reported he would be moving on a free transfer to Watford. Watford later confirmed that he would sign on 1 July 2009.
Severin scored his first goal for Watford in a first round League Cup tie at Underhill Stadium against Barnet on 11 August 2009.
On 1 February 2010, he joined Kilmarnock on loan until the end of the 2009-2010 season. He suffered a triple leg break in a SPL match against Street Mirren on 6 August 2011.
On 17 March 2012, Severin announced his retirement from professional football due to the injury he sustained against Street Mirren. Scotland manager Craig Brown gave Severin his international debut in a 2002 World Cup qualifier against Latvia in 2001.