She was born in Bandon, County Cork, where her father had been Agent to Lord Bandon's Irish estates. Upon retirement, the family moved to Cornwall, buying 'La Pietra' on Paul Hill, Newlyn, the former home of Norman GARSTIN and his wife Constance Mary BIRCH.

Jessica was keen to learn painting and enrolled at the FORBES SCHOOL in 1901-2. She met Frank Gascoigne HEATH, an artist who had settled locally, having himself studied at the school, and they married in 1910. They set up their home initially in Polperro, and had two children by the time Jessica's father paid for them to build their own home, 'Menwinnion', at Lamorna in 1912. They subsequently had another two children.

In WWI Frank was seriously gassed and his health never fully recovered. With heavy family commitments, looking after their children and assisting Frank, she had very little time for painting, but she did exhibit in the mid 1930s.