Captain Thomas Hastings was born Thomas Barnett, the son of a lawyer. Both he and his brother changed their name to that of their maternal great-grandmother in 1812, their father having been convicted of perjury in 1807. Thomas was an officer in the british army 1795–1811, in which he trained as a surveyor, saw service in India and was made Captain from 1799. From 1819 to 1853 he was in the Customs service, mainly in the high rank of Collector.

He was a dedicated amateur painter, draughtsman, watercolour artist and etcher of landscapes, topographical views, marine subjects and coast scenes. As an etcher he became an Associate of the Liverpool Academy, and he exhibited widely—including at the Royal Academy of Arts, the Society of Painters in Watercolours, the British Institution and the Hibernian Academy. He was also a keen promoter of archery and founder of the Carisbrooke Archers Society in 1829.

Hastings was influenced by the Welsh landscape painter Richard Wilson RA (1714–1782). He made forty etchings of paintings by Wilson (two of which he owned) which were published as a series in 1824.