Born as Mary Seton Fraser Tytler in India but brought up in Scotland. 1886 married G. F. Watts. Co-founded the Compton Potters' Arts Guild and the Arts & Crafts Guild in Compton, Surrey. There she also had built the Watts Mortuary Chapel in Compton (1895); and the Watts Gallery (1903–04).
She had been involved with the Postman's Park Memorial to Heroic Self Sacrifice from its inception but on her husband's death in 1904 she took over his role and installed another 37 memorials.