Racing career
Paulsen began his career in 2004 in karting. He switched to the ADAC Volkswagen Polo Cup for 2006, he stayed there for season 2007, taking four victories on his way to finishing third in the championship standings. In 2008, he switched to the Belgian Renault Clio Cup, winning the Junior Cup that year, as well as finishing third in the overall championship standings. He stayed in the series for another year, however only doing a half season, he took one win and finished eleventh in the standings. For 2010, he switched to the SEAT León Eurocup and ended the season thirteenth in the standings. In 2011, he moved to the German SEAT León Supercopa series, having done a single one-off in 2010. He took a single victory on his way to finishing ninth in the championship standings that year. For 2012, he entered the European Touring Car Cups Single-Makes Trophy which allowed him to continue to use his SEAT León Supercopa, he took five victories and never finished out of the top-two in any of the eight races. He eventually won the championship title. In 2014 he returned to the SEAT León Eurocup, taking three wins and six podiums, he finished the season fifth in the championship standings. He continued in the series for 2015 and 2016, taking two victories and six podiums in 2015 as well as finishing second in the standings, while he took three victories and eight podiums in 2016 on his way to finishing third in the standings.
In March 2017, it was announced that Paulsen would race in the TCR International Series, driving a SEAT León TCR for his own team Stian Paulsen Racing.
Paulsen raced in TCR Europe in 2018 and 2019 both for his own team, with a best finish of second in 2018 Hungarian round.
In June 2022, after two years away from races, Paulsen joined Comtoyou DHL Team Audi Sport for TCR Europe fourth round at Norisring in place of Tom Coronel.
After four years from his last race, in May 2026, Paulsen re-joined the TCR Europe grid for the second round of the championship at Spa-Francorchamps once again with his own team: Stian Paulsen Racing.
On 9 July, Paulsen shared via social media his last minute participation in the 2026 TCR World Tour race in Portugal at the Circuito Internacional de Vila Real, driving an Audi RS 3 LMS for British team Vannin Motorsport.
