In the early Middle Ages the name was adopted by Norse raiders and settlers in Ireland in the form Njáll. The Norse transmitted it to England and Scotland, as well as bringing it back to Scandinavia. It was also in use among the Normans, who were of Scandinavian origin. A famous bearer of this name was American astronaut Neil Armstrong (1930-2012), the first person to walk on the moon.
In the United States it became more common for girls in the early 1980s, shortly after the debut of the television sitcom The Facts of Life (1979-1988), which featured a character named Blair Warner. The name left the American top 1000 rankings two decades later, but was resurrected by another television character, this time Blair Waldorf from the series Gossip Girl (2007-2012).