Katherine Gili was born in Oxford in 1948. Her mother Elizabeth wrote two cookery books and her father, Joan Gili, from Catalonia was a publisher, scholar, translator of Lorca and other Hispanic poets. Gili was educated at the Bath Academy of Art in Corsham from 1966-1970 where she studied a two year foundation course and for a Diploma in Art and Design. Her goal was to become a painter, only to become inspired by sculpture in the last term. She spent further time studying sculpture in Corsham. After a year spent at a studio in St Katherines Dock, London she decided she needed more training and enrolled at St Martins School of Art, 1971-1973. She found the environment here much more stimulating and challenging and it gave her the opportunity for serious debate and analysis of sculpture. She described her time at St Martins as like "jumping into the now". The tutors at that time were Alan Gouk, Tim Scott, Philip King, William Tucker and Peter Hide. She also taught for a short time at St Martins after she graduated. She was interested 'in what sculpture can do' and its formal qualities as opposed to any political qualities. After visiting the USA in the early 1970s she was influenced by the work of David Smith and this changed her approach to her work.
In 1973 she was invited by Peter Hide to Stockwell Depot, a studio in South London where she mostly assembled large, formal, abstract sculptures in steel. Her first exhibition at Stockwell Depot was in 1974. She worked alongside other likeminded sculptors including Anthony Smart and John Foster and although the Stockwell Depot artists were never considered as an homogenous group, as they were all too busy on their own work, they would share ideas. Working in a male dominated environment never bothered her as she put her work first. Her notebooks and sketchbooks bear out the kind of work she was doing at this time. She never designed sculpture but worked it out in the process of making it. The notebooks were her way of defining concepts and working out a variety of spacial issues rather than straightforward plans for sculpture, the notebook from her time at St Martins discusses one such concept, 'different ways of breaking a line'. There are also notebooks from her time at Corsham.
Gili left Stockwell Depot in 1978 and became more interested in addressing issues of the 'body' in sculpture moving away from the formal, abstract approach that categorised her work from the 1970s. She became influenced by Alan Gouk's essay 'Proper to Sculpture' and William Tucker's book, 'The Language of Sculpture'. She exhibited at the University of East Anglia, Sainsbury Centre in 1982 for a show called 'Sculpture from Stockwell Depot' and this highlighted her change in direction. In 1984 she was one of the selectors for the 'Sculpture from the Body' show at the Tate Gallery, London.
In 1997 she founded Rokatha Creative Metalwork with her husband, Robert Persey, making ornamental wrought ironwork and metal furniture. She was elected fellow of the Royal British Society of Sculptors in 1999 and she is referred to in Jorge Lewinski's book 'Portrait of the Artist'.