[2] Until the age of 20, Guldborg Christensen played for the local team Akademisk Boldklub, where he in 2001 made his senior debut in the Danish Superliga.

[6] He soon established himself as a regular starter at the centre back position, whilst being a part of a successful promotion campaign to Allsvenskan in 2014.

[7] Guldborg Christensen left the club by mutual consent in May 2015, failing to make a single appearance for "Bajen" in Allsvenskan.

[9] Guldborg Christensen returned to his native country in August 2015, signing a two-year contract with Lyngby BK in the Danish second tier.

[10] On 7 December 2017, he announced his retirement to instead work for the Danish Football Association as a coordinator for the youth national teams.