Born in Aalborg, Denmark, Mads Korneliussen is the son of Karl Erik Korneliussen and younger brother of Tim Korneliussen, both former riders. Mads took up speedway in 1993.[3][4]
He made his debut in British speedway in 2003 with Newport Wasps in the Premier League, also doubling-up in the Elite League in 2005 with Swindon Robins.[3] In 2006 he rode full-time in the Elite League with Swindon.[6] His 2007 season was marred by a series of injuries, but he returned to Swindon in 2008 as part of the team that won the Elite Shield. After a season with Peterborough Panthers in 2009, he returned to Swindon in 2010 before moving to King's Lynn Stars in 2011 where he rode for three seasons.[7]
After being left out of the Stars team for 2014 he signed for Leicester Lions. He started the season with his testimonial meeting at King's Lynn marking ten years in British speedway.[8][9] In 2014, he rode in the Elite Riders Championship as a late replacement for Jason Doyle.[10]