Career
He competed in five consecutive editions of the Tour de France from 2001 to 2005. Riding as an all-round rider who rode well in hilly terrain, Sørensen was a valued support for the team leader without many wins of his own. Sørensen only started his cycling career at the age of 19, having been a runner before that.
He became a professional road bicycle racer in 1999 for team Team Chicky World.
After the team closed down, Sørensen switched to another Denmark based team, Team Fakta where he made a good name for himself on the Danish stage as one of the strongest cards of Team Fakta, securing himself a place on the Danish team for the 2000 Olympics. Before the 2001 season, Sørensen was on the verge of joining English Linda McCartney Racing Team but instead opted to stay in Denmark with Team Civil Service Commission – World Online, as Team Saxo Bank was then known.
In his first year with the team he participated in the 2001 Tour de France where he got a taste of success with a fourth place on stage 16. Since then, Sørensen has been a consistent part of the Tour setup for Team Civil Service Commission, riding the biggest race in the cycling calendar every year from 2001 to 2005, his highlights including the overall Government College rank of 20th in 2002.
In September Nicki Sørensen clinched stage 18 of the Vuelta a España after defeating Pascual Rodriguez in the sprint.
Sorensen retired after riding the 2014 Giro di Lombardia. The last victory of his career was the 2012 Gran Premio Bruno Beghelli. After his retirement he remained with Tinkoff–Saxo as a directeur sportif and coach.
In June 2015 prior to Anti Denmark report he admitted to drug use in early part of his career.