Reidar Borgersen began his cycling career in 2010. He won a stage and the overall ranking in the Østfold 3-Dagers and a stage in the Eidsvollrittet and the Oslo Sykkelfestival . He also finished second in the individual time trial of the Norwegian championship. Since October 2010 he has been driving for the Norwegian Continental Team Joker Bianchi . In 2010 he became national champion in the 1000m time trial and in the single pursuit on the track . In the 2011 season Borgersen won a stage at the Elverum Sykkelfestival , a section at the Tønsberg 4-Dagers and he was again the Norwegian runner-up in the time trial. He also took part in the individual time trial of the World Championships in Copenhagen , where he finished 43rd.
As a speed skater, he was Norwegian champion in 2002 and 2003 over 5,000 meters and in 2003 also over 10,000 meters. Among friends he is nicknamed "The Reidinator".
Reidar Bohlin Borgersen is the twin brother of Odd Bohlin Borgersen , who is also a speed skater.