Born in Revúca, Danko studied at the Faculty of Law at Comenius University in Bratislava.

[1] After compulsory military service, Danko founded several commercial companies and worked as an independent lawyer.

[3][4] In September 2016, while in his position as the Speaker of the Parliament, Danko was promoted by eight ranks (from OR-4 to O-2), to Captain in Reserve of the Slovak Army, by Minister of Defence Peter Gajdoš.

When media showed interest in his thesis, he asked the university to ban public access to it.

[9] According to the conclusion published by the commission in January 2019, the rigorous procedure met valid regulations, but the thesis contains parts that only slightly differ from original sources, most of the thesis is the same to a large extent and it preserves also the structure of sources without proper citation or paraphrasing.