Lexy Ferguson was the youngest child of Roderick Ferguson and his wife Marion MacKillop. She was born in Borgh Mhor, Harris in 1850, where the family was living at the time. In 1854 they returned to Berneray where her father had obtained the croft at 10 Ruisgarry (Gunhill).

Lexy worked as a domestic servant before her marriage in 1869 to Peter MacAskill of 4b Ruisgarry (Tarraloch), with whom she had nine children.