She was the only daughter and heir of Aymer Taillefer, Count of Angoulême, by Alice of Courtenay, who was sister of Peter II of Courtenay, Latin Emperor of Constantinople and granddaughter of King Louis VI of France. Isabella became Countess of Angoulême in her own right on 16 June 1202, by which time she was already Queen of England. Her marriage to King John took place on 24 August 1200, at Bordeaux,
In the spring of 1220, she married Hugh X of Lusignan, "le Brun", Seigneur de Luisignan, Count of La Marche, the son of Hugh IX, to whom she had been betrothed before her marriage to King John. It had been previously arranged that her eldest daughter Joan should marry Hugh, and the little girl was being brought up at the Lusignan court in preparation for her marriage. Hugh, however, upon seeing Isabella, whose beauty had not diminished, preferred the girl's mother. Princess Joan was provided with another husband, King Alexander II of Scotland, whom she wed in 1221. Described as "vain, capricious, and troublesome", Isabella could not reconcile herself to the necessary loss in rank which resulted after her marriage to the Count of La Marche. Isabella had been a Queen of England and deeply resented having to give precedence to women who were now of higher rank than she, a mere Countess of Angoulême and La Marche