Samuel Johnson approved of him as a Jacobite, and gave him a place on the team of six helpers he used on his Dictionary.
Shiels was recommended to Ralph Griffiths and employed on the Lives of the Poets of Great Britain and Ireland to the time of Dean Swift (London, 5 vols.
The compilation was mainly based on work of Gerard Langbaine and Giles Jacob, with the help of Thomas Coxeter's.
The later volumes are ascribed on the title-page to Cibber ‘and other hands.’ Apart from his compilations, Shiels wrote a didactic poem on ‘Marriage’ in blank verse (London, ‘at the Dunciad in Ludgate Street,’ 1748), and another piece in praise of Johnson's ‘Irene,’ called ‘The Power of Beauty’ (printed in George Pearch's ‘Collection,’ i.
Shiels venerated his countryman James Thomson, on whose death he published an elegy, ‘Musidorus’ (London, 1748).