In 1939, Kathleen got married to John Oliver Archer. Being one of the ablest professional intelligence officers, she was not involved in any other love affairs beside this one.
Though Kathleen was born in Bengal, she moved to London at a young age and she began studying there. Though she was just 18 years old, she was recruited to MI5 and from that time on she began serving in the Britain's Security Service. She also earned one title during her early days and that was one of MI5's most remarkable wartime recruits. The actual figure about her salary and net worth is unknown.