She was the posthumous and only child of Edward Talbot, second son of William Talbot, bishop of Durham, and his wife Mary (died 1784), daughter of George Martyn, prebendary of Lincoln. Her uncle Charles Talbot, another son of the bishop, was lord chancellor. Her father, Edward, who was elected fellow of Oriel College, Oxford, and appointed archdeacon of Berkshire in 1717, died on 9 December 1720.
Catherine"s education was superintended by Secker. She also painted in watercolours and read widely. As a child her talent was recognised, for example by Thomas Rundle.
The two ladies carried on a lively and copious correspondence.
As Secker was successively rector of Saint James"s, Westminster, bishop of Oxford, dean of Saint Paul"s, and finally in 1758 archbishop of Canterbury, Catherine Talbot frequented the society of her time. She knew among others Bishop Butler, Lord Lyttelton, William Pulteney, earl of Bath, Montagu, the Duchess of Somerset, with whom she often stayed at Percy Lodge, and Samuel Richardson.
Richardson discussed Sir Charles Grandison with her and Elizabeth Carter, adopted their suggestions, and sent them parts of the novel to read before publication. Catherine Talbot visited Richardson at North End, Hammersmith.
She also encouraged Carter to translate Epictetus, and corresponded with her on the subject while the work was in progress.
During the whole period of her residence with him Catherine Talbot was Secker"s almoner. In 1760, accompanied by Elizabeth Carter, she went to Bristol for her health. The ladies moved from Lambeth Palace to Lower Grosvenor Street.
There Catherine died of cancer on 9 January 1770, aged 48.
Several poems were written in her praise.
