Clare Leighton was born in London on 12 April 1898, the daughter of Robert Leighton (18581934) and Marie Connor Leighton (18671941), both authors. She was baptised with the name Clare Marie Veronica Leighton on 26 May 1898 at All Saints' Church in St John's Wood. Clare lived her early life in the shadow of her older brother, Roland - her mother's favorite; the family nickname for Clare was "the bystander". Her mother was dismissive of Clare's looks, ambitions and talents, while she said of Roland that: "He is the only one of my children who is beautiful enough to be worth dressing". Nevertheless, Clare's 1947 biography of her mother "Tempestuous Petticoat: the story of an Invincible Edwardian" succeeded in "making her readers envy this fantastic mother, even share some of the affection which she feels for her."