It was not until she reached the age of 22 that Xenia de Jong competed at her first Dutch Championships, reaching the 4th place at the 1944 edition. Shortly after the war, she married Mike Stad, a football player and distance runner. After the birth of her first child in 1947, she returned, qualifying for the 1948 Olympics. Individually, she reached the semi-finals of the 100 metres, but with the Dutch sprint relay team she won a gold medal. Stad-de Jong ran the first leg of the race, which was anchored by Dutch star Fanny Blankers-Koen, who earned her fourth gold of the Games. Stad-de Jong returned to athletics in 1950, after giving birth to her second child in 1949. With the Dutch relay team she narrowly missed the European title, being defeated by the British women in a photo finish. She continued to compete for the Dutch national selection, but was not chosen to compete in the Helsinki Olympics in 1952. She retired several years later due to an injury, but remained involved with her sport as a club track coach. In 2004, at age 82, she was chosen to carry the Olympic Flame when it passed through Amsterdam on its way to Athens.
Personal Best: 100y – 11.4 (1948); 100 – 12.2 (1948); 200 – 25.7 (1950).