Career
Oxenstierna belonged to one of the oldest noble families of Sweden, which is known from the 13th century. In 1917 he became a Navy officer and in 1932 appointed naval attaché in Paris. Upon his return to Sweden he was promoted to Lieutenant Commander.
During World World War II he served as a defense attaché in London.
His enciphered cables to his government were treacherously passed on to the Germans by a code clerk in Stockholm who deciphered them, becoming a major source of naval intelligence to the Nazi regime. He retired in 1954 in the rank of sea captain.
They divorced in 1946, and Oxenstierna remarried the same year.