He was born on 19 September 1759 at Witnesham, Suffolk, and studied at Ipswich School and Caius College, Cambridge, where he graduated in 1781.

[6] Kirby was brought to the study of natural history by Nicholas Gwynn (a friend of Boerhaave's), who introduced him to Sir James Edward Smith in 1791.

Among his early friends were the naturalists Charles Sutton and Thomas Marsham, with whom he made lengthy scientific excursions, as later with William Jackson Hooker and others, becoming a leading parson-naturalist.

To make the naturalist a religious man – to turn his attention to the glory of God, that he may declare his works, and in the study of his creatures may see the loving-kindness of the Lord – may this in some measure be the fruit of my work…' (Correspondence, 1800) This, the first scientific treatise on English bees, brought him to the notice of leading entomologists in Britain and abroad.

Extensive correspondence followed with scientists including Alexander Macleay, Walkenaer, Johan Christian Fabricius and Adam Afzelius.

In 1832, he helped to establish an early museum in Ipswich under the aegis of the town's Literary Institute, and presented a herbarium and a group of fossils.

With Spence, he helped to found the Entomological Society of London in 1833, with John Westwood as Secretary, and became its Honorary President for life.

[5] Kirby was the original President of the Ipswich Museum, 1847–50, fulfilling a project which he had advocated since 1791, and appeared with William Buckland and others at the opening ceremony.

[5] Besides the books already mentioned he was the author of many papers in the Transactions of the Linnean Society, the Zoological Journal and other periodicals; Strictures on Sir James Smith's Hypothesis respecting the Lilies of the Field of our Saviour and the Acanthus of Virgil (1819) and Seven Sermons on our Lords Temptations (1829).