Yoors was born in Antwerp, Belgium. At the age of 12, he ran away with a group of Romanies, or Gypsies, travelling with them for several months. When he finally returned home, rather than scold him, his liberal-minded parents gave him permission to spend part of each year with the Romanies, which he did until age 18. Later in life, he wrote a book called The Gypsies about his experiences with them. The book, considered a seminal work, is a rare insider's account of Gypsy life. The Gypsies includes a number of gypsy words and Yoors suggests that variations of the original Sanskrit have occurred, over the years, between the various tribes. The one area where the differences are minimal is in the adages, a favourite reflection of the gypsy view of life and the world around them. The adages Yoors has quoted are word-for-word the same as those used by English gyspies and those of Zincali/Gitano gypsies from Spain.
Jan Yoors wrote another book entitled Crossing and took all of the photographs for the book Only One New York.
Jan Yoors was also a popular artist during the nineteen sixties. His art ranged from paintings to the large tapestries that made him famous.
A profile of Yoors entitled "A Gypsy for Our Time" appears on pp. 15–30 of Finding the Trapdoor: Essays, Portraits, Travels (1997), by Adam Hochschild.