Although a native New Yorker, Catherine spent some of her most formative years in London, where her mother still lives. She is the daughter of American business man Howard Oxenberg (a New York City dress manufacturer) and of Princess Elizabeth of Yugoslavia and serbia (born in Belgrade, Serbia, in 1936). Catherine's sister Christina Oxenberg (born 1962), is a writer, and they also have a younger half-brother, Nicholas Balfour (born 1970).

Catherine's parents split up when she was six and divorced in 1969, and Princess Elizabeth married English banker Neil Balfour (born in Peru in 1934) the same year, moving with him to England. From the age of eight, Catherine lived and went to schools there, then in 1977, when she was sixteen, her mother and step-father separated and were divorced. In the mean time, Catherine had moved back to the U.S. to go to St Paul's School, Concord, New Hampshire, a smart prep school. She graduated from St Paul's in the class of 1979 summa cum laude and went on to Harvard. She transferred to Columbia, where she read psychology, philosophy and mythology, after deciding to pay her own way through college. While at Columbia, Catherine became a successful fashion model, before trying her hand at acting. Her first acting coach was Richard Burton, who was engaged to her mother at the time. (Elizabeth broke up with Burton and married thirdly Dr Manuel Ulloa y Elias, a former prime minister of Peru.)

In 1981, Catherine turned down an offer of marriage from her cousin Prince Andrew, second son of Queen Elizabeth II, and it may be that after that her suitors had a hard act to follow. She has been married twice, first to the much older film producer Robert Evans (they were married and divorced in ten days in July 1998), then to Casper van Dien (8 May 1999). Catherine has three daughters, India Riven Oxenberg, born in India on June 7th, 1991, Maya van Dien, born in Los Angeles on September 20th, 2001, and Celeste Alma van Dien, born October 3rd, 2003.

Catherine is a second cousin of the Prince of Wales and of Queen Sophie of Spain. Through her grandparents, Prince Paul, Regent of Yugoslavia from 1934 to 1941, and Princess Olga of Greece and Denmark, Catherine is directly descended from dozens of crowned heads, including kings and queens of Greece, Scandinavia, and England and Russian Tsars such as Alexander II (1818-1881), Nicholas I (1796-1855), Paul I (1754-1801), and Peter III (1727-1762). Indeed, her parents are said to have named their eldest daughter after her five-times-great-grandmother Catherine the Great, Empress of all the Russias (1729-96).

Catherine's sister Christina Oxenberg was married to Damian Elwes, the artist brother of English actor Cary Elwes, but they had no children and are divorced. Her brother Nicholas Balfour married Stéphanie de Brouwer in 2000. Catherine`s first niece, India Balfour, was born in 2002.

In May and June, 2004, Catherine joined her mother, Princess Jelisaveta Karadjordjevic, in Belgrade, Serbia, to support her in the final weeks of her election campaign - she was running as President of her home country. In the first round election held on June 13, 2004, Princess Jelisaveta came sixth out of fifteen candidates and then supported the Democratic Party's Boris Tadic, who was elected as President in the second round election held on June 27, 2004.

Catherine was portrayed by Rachael Taylor, in the 2005 telemovie Dynasty: The Making of a Guilty Pleasure, a fictionalized retelling of the behind the scenes goings-on during the production of Dynasty. In 2006, Catherine Oxenberg appeared in the TV special, Dynasty Reunion: Catfights & Caviar, in which she reunited with her former Dynasty castmates to reminisce about the series.