Working first as a schoolteacher and later solely as a collector, he assembled and published a huge amount of detailed information on all aspects of folklore as he visited country people throughout his native Jutland.

In the area where he was teaching, he soon discovered a wealth of songs and ballads, some dating back to the Middle Ages, which he recorded and, thanks to financial support from fellow collector Svend Grundtvig, published as Jyske Folkeminder I-II (1871–76).

In 1924, he donated all his published works and manuscripts to that institution while leaving most of his other possessions of folkloric interest to the museums at Herning and Vejle.

He himself recorded some 3,000 songs with 1,000 tunes, 2,700 fairy tales, 2,500 jokes, 25,000 legends, numerous sayings, poems and riddles as well as tens of thousands of descriptions of traditions and everyday life.

His special qualities as a folklore collector were noted by his friend and colleague Hakon Grüner-Nielsen who emphasized his mastery of local dialects, his exceptional memory and his rigorous approach.

[2] Tang Kristensen contributed greatly to the method of collecting folklore by going directly to the sources of oral tales, often recording the narritive tone of his informants.