Christabel Mary Burton was born in Hertfordshire to Anglo-Irish parents. Her mother, also named Christabel (née Harmsworth), was the sister of Lords Northcliffe, Harmsworth and Rothermere. Christabel Mary won a scholarship to Oxford but decided to study music in Germany. While there she met Peter Bielenberg (1911-2001), two years her junior, who was studying law with a view of joining his father's practice in Hamburg.

They married in 1934 and she took German citizenship, which required her to relinquish her British citizenship. The Bielenbergs lived initially in Hamburg, then moved to Berlin and had three sons, Nicholas, Christopher and John. The heavy Allied bombing raids led Mrs Bielenberg and her children to leave the city, and they eventually settled in the village of Rohrbach in the Black Forest.

Both Christabel and Peter Bielenberg were opposed to Nazism and following Hitler's rise to power in 1933, participated in anti-Nazi activity. Peter Bielenberg was a close friend of Adam von Trott zu Solz, who was involved in the von Stauffenberg bomb plot against Adolf Hitler of 1944, and as a result of his suspect political views and this close association was arrested, interrogated and imprisoned in Ravensbrück concentration camp following its failure.In an effort to secure his release, Christabel Bielenberg asked to be interviewed by the Gestapo in order to convince them of her and her husband's political naivety and innocence. She was successful and he was released to a punishment unit but mistakenly allowed leave before joining it. He managed to slip away and remained in hiding near his family until the fighting ended.

After the war, she returned to the UK with her children, visiting Germany as a war correspondent. In 1948, the family settled in Tullow, County Carlow, Ireland, buying a dilapidated farm called "Munny House", which they transformed into a commercial success . As well as writing her autobiography she became involved with the Irish Peace Marches of the 1970s and lectured in Germany. She was made a Commander of the German Federal Order of Merit and was also awarded a Gold Medal of Merit by the European Parliament.

Her experiences in World War 2 were made into the TV drama Christabel by the BBC in 1988. Elizabeth Hurley starred in the title role. Christabel's experience of attempting to shelter Jews hiding from persecution was described by her in the television series The World at War in 1974.

Christabel Bielenberg sat for sculptor Alan Thornhill for a portrait in clay. The correspondence file relating to the Bielenberg bust is held in the archive of the Henry Moore Foundation's Henry Moore Institute in Leeds and the terracotta remains in the collection of the artist.

She had three sons, Nicholas, John and Christopher. Nick's son Andy is a historian at University College Cork; Kim works as a journalist in Dublin. Nicholas's wife was Charlotte, daughter of Fritz-Dietlof von der Schulenburg.