Her diaries and correspondence are an important source of information about Samuel Johnson. She was an author in her own right and her ana Thraliana is important because it was almost, if not quite, the first English Ana.
This was her entry to London society, as a result of which she met Samuel Johnson and other literary figures, including the young Fanny Burney. Johnson visited Wales in Mrs Thrale's company on several occasions. In 1775 he wrote verse in celebration of her 35th birthday, and the same year wrote Latin verse in her honour.
Following Thrale's death in 1780, Hester married Gabriel Mario Piozzi, an Italian music teacher. This caused a rift with Samuel Johnson which was only mended shortly before his death. With her second husband, she retired to Brynbella, a specially-built country house on her Bach y graig estate, in the Vale of Clwyd, south of - and close to - Tremeirchion village in north Wales.
She died in at Royal York Crescent, Clifton, Bristol. She was buried on 16 May 1821 near Brynbella in the churchyard of Corpus Christi Church, Tremeirchion. A plaque inside the church is inscribed "Dr. Johnson's Mrs. Thrale. Witty, Vivacious and Charming, in an age of Genius She held ever a foremost Place".