Wolcot was born in Dodbrooke, near Kingsbridge, Devon He was educated by an uncle, and received his M.D. from Aberdeen University. In 1767 he went as physician to Sir William Trelawny, Governor of Jamaica, who he persuaded to present him to a church in the island then vacant. He was ordained in 1769. Sir William died in 1772, when Wolcot came home and, abandoning the Church, resumed his medical career. He settled in practice at Truro, where he discovered the talents of John Opie, and assisted him.
In 1780, Wolcot went to London and began writing satires. The first objects of his attentions were the members of the Royal Academy. These attempts being well received, he soon began to fly at higher game, the King and Queen being the most frequent marks for his satirical shafts. In 1786 he published The Lousiad, a Heroi-Comic Poem, which took its name from a legend that a louse had once appeared on the King's dinner plate.
Other objects of his attack were Boswell, the biographer of Samuel Johnson, James Bruce, the Abyssinian traveller, Hannah More, former bluestocking and playwright, and Bishop Porteus. Wolcot had a remarkable vein of humour and wit, which, while intensely comic to persons not involved, stung its subjects to the quick. He had likewise strong intelligence, and a power of coining effective phrases. In other kinds of composition, as in some ballads which he wrote, an unexpected touch of gentleness and even tenderness appears. Among these are The Beggar Man and Lord Gregory. Much that he wrote has now lost all interest owing to the circumstances referred to being forgotten, but enough still retains its peculiar relish to account for his contemporary reputation.