Troels-Lund was born in Copenhagen, the youngest son of Henrik Ferdinand and Anna Cathrine Lund.
From 1870 to 1875 he was an assistant at the Gehejmearkivet, and an instructor in history at the Royal Danish Military Academy starting in 1874, serving as a full professor there from 1888 to 1900.
The work vividly detailed everyday life in sixteenth century Scandinavia, and is considered a characteristic example of Danish cultural history.
His work said little about kings, armies and governments, but instead concentrated attention on the lives of the ordinary men and women of the age with which he deals.
He used these common people to illustrate a vast body of documents previously neglected by the official historians.