In the 2000s, Nielsen began her political career with the European Parliament as a consultant before working for the Ministry of Gender Equality as a deputy minister.

[1] She started her career at the European Parliament as a consultant from 2002 to 2004 before becoming a deputy minister of the Ministry of Gender Equality until 2009.

[3] As Minister for Higher Education and Science, Nielsen declared in 2014 that 4,000 student admissions to low turnover programs would be cut.

[4] Universities Denmark later negotiated a deal with her to have the number of cuts lowered and implemented starting in 2018.

[5] On 28 June 2015, Nielsen was replaced by Esben Lunde Larsen for the position of Minister for Higher Education and Science.