Jens Jacob Asmussen Worsaae was born in Vejle, Denmark, in 1821. His was a wealthy, educated family.

In 1838 he started studies at the University of Copenhagen, graduating in 1841. While in Copenhagen for college, Worsaae began to work as a volunteer with Christian Jürgensen Thomsen, the first director of the National Museum of Denmark. He learned Thomsen's methods of dating artifacts and controlled archaeological excavation.

Not wanting to continue working without pay, he found a patron in King Christian VIII. At the king's request, Worsaae wrote an overview of the antiquarian field: The Primeval Antiquities of Denmark (Danmarks Oldtid oplyst ved Oldsager og Gravhøie), which explicated archaeology and the three - age system, was first published in 1843 in Denmark, and became widely popular. More than Thomsen, Worsaae reacted against the then prevalent view of prehistory in Denmark. The historian Suhm identified the proto - historic period as the ”legendary age”. He thought it could be studied from the Old Norse myths and legends. Suhm interpreted Norse gods and mythical figures as the kings and leaders of prehistoric peoples. Worsaae rejected this view of prehistory as euhemerism. He thought that prehistory was a period best studied not by historians, but by archeologists, who dealt with material goods. He believed that the knowledge that can be obtained about prehistory will necessarily be qualitatively different from the knowledge of historic periods, based on written texts.

Worsaae was working in a context of nationalist striving. In the mid 19th century, amid Danish - German political tension, the Norwegian scholar and nationalist Peter Andreas Munch provided the Germans with arguments for invading Denmark by suggesting that Denmark had originally been settled by Germans. But, Worsaae argued that the prehistoric peoples of the archaeological records could not be identified with any modern peoples because of the sheer timescale involved. Still, his work on Danish antiquities was taken to mean that natives had a long history in the area.

Similarly, when the Haraldskær Woman, a peat - bog mummy was found in southern Denmark in 1843, she was exhibited as the legendary Queen Gunhild of the early Mediaeval period. Worsaae disputed this view, arguing that the body was Iron Age in origin, like most from the bogs, and predated any historical persons of the chronicles by at least 500 years.

King Christian sent him on a research trip to Britain and Ireland in 1846 and 1847, to study evidence of Vikings. He did research into antiquities and histories to develop an account of the culture around the North Sea. Worsaae wrote An Account of the Danes and the Norsemen in England, Scotland and Ireland (1852).

In 1847 Worsaae was appointed the Inspector for the Conservation of Antiquarian Monuments. He worked to preserve areas and directed excavations across the country. By controlled excavation and analysis of stratigraphy, he found artifacts that supported Thomsen's Three - Age System, formerly based on the museum collection. Using Nilsson's studies of prehistoric subsistence and the Danish geologist Johannes Japetus Steenstrup's studies of changes in prehistoric forestation, Worsaae began to explore the limits of what can be known about prehistory. In that period of scholarship, those who could grasp the concept of prehistory were hard pressed to imagine that cultural developments could be discerned within the three ages. Through excavations of stone age sites, Worsaae saw that there were distinct trends of coöccurrence: a period with simple tools, signs of hunting and fishing, and with dog bones as the only evidence of domestic animals. This period was associated with the discovery of “kitchen middens”: enormous piles of waste produced by oyster eating foragers. The middens were sometimes as large as ten meters high and a hundred meters long. Worsaae commented in his diary that ”these enormous piles of oyster shells must represent the remains of meals eaten by stone age people.”

Worsaae determined that a second subset of the Stone Age deposits, associated with dolmen burials, showed signs of animal husbandry and agriculture. Following Nilsson's analyses of prehistoric subsistence, Worsaae proposed that the Stone Age had a foraging period and an agricultural period, which could be demonstrated from artifacts. He also recognized that finds from caves in France predated even the Danish foraging stone age period. He was perhaps the first to envision what became the division between Paleolithic, Mesolithic and Neolithic periods. These were classified and named by the British researcher John Lubbock, 1st Baron Avebury in 1865.

As director of the National Museum of Denmark for nearly two decades (1856 - 1874), Worsaae became the mentor of a new generation of archaeologists: including Sophus Müller in Denmark. He was also a professor at the university. He supported archaeology as a science and influenced its study and excavation practices. He also influenced archaeologists in Sweden, where Nils G. Bruzelius, Hans Hildebrand and Oscar Montelius followed his lead. They further developed methods for establishing chronologies through controlled excavations.

Worsaae's early work, The Primeval Antiquities of Denmark (Danmarks Oldtid oplyst ved Oldsager og Gravhøie), which explicated the three - age system, was first published in 1843 in Denmark, and in English in 1849. It strongly influenced researchers in Great Britain and the United States. For instance, Lewis Henry Morgan, a pioneering American ethnologist, developed his own three - stage system of prehistory in his book, Ancient Society (1877). He theorized that prehistoric peoples went through progressive stages of "savagery", "barbarism" and "civilization", to be traced by several criteria, including their kinship and social structures, as well as tools and cultivation.