She is the daughter of Swedish landscape Painter Henry Mayne (1891–1975). In 1944 her father-in-law Ruben Rausing (1895–1983) founded Tetra Pak, which revolutionized the packaging of liquids such as juices and milk. The company was inherited by his sons Gad and Hans. In 1996, Gad bought his brother's half of the company. When Gad died in 2000, his wife Birgit and their three children inherited packaging giant Tetra Laval.
Birgit Rausing and her family had an estimated net worth of US$13.0 billion in 2010. She is the third wealthiest person in Sweden, according to Forbes magazine.
The Lahore University of Management Sciences (LUMS) library has been renamed as Gad & Birgit Rausing Library to acknowledge the donation provided by the Rausing family to construct the library building. Mr. Dennis Jönsson, CEO Tetra Pak inaugurated Gad & Birgit Rausing Library on Thursday, March 17, 2011. Mr. Jönsson appreciated that the funds donated by the Rausing family were utilized for educational purposes. He also unveiled a plaque commemorating the Rausing family's donation for development of the library building.