He was born at Rushay in the parish of Bagber, Dorset, the son of a farmer. After being a solicitor's clerk and for a while keeping a school at Mere in Wiltshire, he was ordained into the Church of England in 1847, taking a BD degree from St John's College, Cambridge, in 1851. He served curacies at Whitcombe, Dorset, 1847-52, and again from 1862. Between 1860-62 he held a curacy at Rotherham in Yorkshire. He became rector of Winterborne Came with Winterbourne Farringdon, Dorset, from 1862-86.

He first contributed the Dorset dialect poems for which he is best known to periodicals, including Macmillan's Magazine; a collection in book form Poems of Rural Life in the Dorset Dialect, was published in 1844. A second collection Hwomely Rhymes followed in 1858, and a third collection in 1863; a combined edition appeared in 1879. A "translation", Poems of Rural Life in Common English had already appeared in 1868.

His philological works include Philological Grammar (1854), Se Gefylsta, an Anglo-Saxon Delectus (1849). Tiw, or a View of Roots (1862), and a Glossary of Dorset Dialect (1863).

Among his other writings is a slim volume on "the Advantages of a More Common Adoption of The Mathematics as a Branch of Education, or Subject of Study", published in 1834.

He was a friend of Thomas Hardy, Alfred Tennyson and Gerard Manley Hopkins.

Barnes had a strong interest in language; he was fluent in Greek, Latin and several modern European languages. He called for the purification of English by removal of Greek, Latin and foreign influences so that it might be better understood by those without a classical education. For example, the word "photograph" (<Gk. light+writing) would become "sun-print" (