From 1710 he acted as assistant tutor, and early in that year he was attracted by the Advice for the Study of Divinity in William Whiston's Sermons and Essays (1709).
Alexander Gordon in the Dictionary of National Biography tentatively identified him as the Hallett who, according to Evans's list, was minister for a time to a congregation at Martock, Somerset.
He signed the disclaimer of Arianism (6 May 1719) drawn up by his father, and took part in the controversy which divided the Exeter assembly, aiming to reconcile the unity of God with a recognition of the Son as subordinate deity.
[1] The outcome saw the elder Hallett and James Pierce excluded from their meeting-house, and the academy shut down.
When Peirce died (1726) his place was taken by Thomas Jeffery, formerly a student at the elder Hallett's academy.