Kynaston, second son of Roger Kynaston, by his marriage to Georgiana, third daughter of Sir Charles Oakeley, governor of Madras, was born at Warwick in 1809 and educated at Westminster School from 1823. He was admitted to Christ Church, Oxford, in 1827, and matriculated on 30 May. He obtained the college prize for Latin verse (subject, Scythae Nomades) in 1829, took a first-class in Classics in 1831, and was appointed tutor and Greek reader in 1836. He graduated BA in 1831, M.A. in 1833, and BD and D.D. in 1849.
At the university he was select preacher in 1841, and was subsequently a lecturer at his college in philology, a subject to which he was much devoted, and to which he continually directed the attention of his pupils. In 1834 he was ordained, and served as curate of Culham, Oxfordshire. Four years later, at the early age of twenty-eight, he was elected High Master of St. Paul's School, London, on the retirement of Dr John Sleath. During the thirty-eight years of his successful rule he numbered among his scholars many who grew up to be distinguished men. Messieurs Demogeot and Montucci, the French commissioners who visited the school in 1866, especially mention the paternal manner in which the High Master dealt with the boys. Lord Truro, an Old Pauline, presented him in 1850 to the city living of St. Nicholas Cole Abbey, with St Nicholas Olave, which he held until the parishes were amalgamated with St. Mary Somerset in 1866. He resigned the mastership of St. Paul's in 1876, and the only preferment which he held at the time of his death was the prebendal stall of Holborn in St. Paul's Cathedral, to which he was presented by Bishop Blomfield in July 1853.
Death and legacy
He died at 31 Alfred Place West, South Kensington, on 26 October 1878, and was buried at Friern Barnet on 2 November. He had married in 1838 Elizabeth Selina, daughter of Hugh Kennedy of Cultra, co. Down.
Kynaston's taste and scholarship led to his selection as a candidate for the chair of poetry at Oxford in 1867, but he was defeated by his college contemporary, Sir Francis Hastings Doyle. Few scholars of his age surpassed him as a composer of Latin verse. He was the author of numerous poetical compositions in praise of Dean Colet, the founder of St. Paul's School, which were produced each year at the apposition. Among these the Number of the Fish, 1855, and the Lays of the Seven Half-centuries, written for the seventh jubilee (1859), are the best known. To the outer world he was most familiar as a writer and translator of hymns. In the library at St. Paul's School are an engraved portrait of Kynaston and a marble bust by G. Halse, indeed to this day the school's Classic's department maintains a Kynaston Prize in his honour.
- Psittaco suum Chaire, 1840.
- Miscellaneous Poetry, 1841 (contains reminiscences of his life as a curate).
- Prolusiones Literariæ in D. Pauli Schola recitatæ comitiis maximis, 1841.
- Terentii Adelphorum Prologus et Epilogus, 1842.
- Strena Poetica, 1849.
- Commemoration Address in praise of Dean Colet, 1852.
- Ho Arithmos tōn ichthyōn. By the Scholæ Paulinæ Piscator primarius, 1856.
- Ipsum Audite. Hymnus super fundatione D. Pauli Scholæ, 1857.
- The Glory of Paradise. By Peter Damiani, edited, with a translation, 1857.
- Puerorum centum quinquaginta trium canticum centenarium. Rhythmus in D. Pauli Scholæ auditorio modis admixtis recitatus, 1858.
- Rete Coletinum, 1861.
- Saturnalium Intermissio. Carmen Latinum in divi Pauli Schola recitatum, 1862.
- Occasional Hymns. Original and Translated, 1862; 2nd ser. 1864.
- The Number of the Fish. A Poem on St. Paul's School, 1864.
- Doce, Disce aut Discede. Carmen elegiacum anniversarium, 1864.
- Cantica Coletina, quotidiana anniversaria centenaria, 1867.
Besides a number of minor pieces in pamphlet form, including Coleti Torquis, 1867, Comitiorum Coletinorum Intermissio, 1871, Missiones Coletinæ, 1873, Coleti Sepulcrum, 1873, Kynaston also wrote a long series of Latin hymns in the Guardian, the last of which, entitled Ichthyōn katalogos, was recited at the "Winter Speeches" of 1876, when Kynaston retired from office.