Gwynn, Lucius Henry (1873–1902), cricketer and rugby international, was born 5 May 1873 at Ramelton, Co. Donegal, fourth of seven sons of the Very Rev. John Gwynn (qv), clergyman and author, and Lucy Josephine, eldest daughter of William Smith O'Brien (qv) of Cahirmoyle, Co. Limerick. Educated at St Columba's College and TCD, where he was elected a fellow (1899), he enjoyed a prodigious, if shortlived, career in both cricket and rugby.
Despite his slight build, he was an elusive, enterprising rugby centre and won seven caps during 1893–8. He was an ever-present in the team that won Ireland its first triple crown (1894), a feat that included a first-ever victory on English soil. When Ireland regained the triple crown (1899), he was a selector, and by then had moved to Monkstown RFC. His younger brother, Arthur Percival, also played for Ireland against Wales (1895), and they were joined by a third brother, Robert, in the Leinster team.
Gwynn was also regarded as Ireland's finest batsman of the period. A right-handed opener whose front-foot drives were a trademark, he was sought after by English teams and would have played regular first-class cricket had he lived in England. Playing with the Dublin University XI in 1895 he scored 63 and 106 not out against Cambridge, and 153 not out against Leicester. This led to an invitation to play for the Gentlemen of England (1895–6). He scored 81 not out playing for Sir T. C. O'Brien's (qv) Irish XI against W. G. Grace's England XI (1902). In that 1902 season he scored over 1,000 runs at an average of over 50 and made four centuries. His career batting average of 44.38, comprising a total of 577 runs in 11 matches, gave him the best average of any Irish batsman before the second world war. He also took 14 wickets for Ireland.
He married Katherine Rawlinson, daughter of Maj. Rawlinson of Bristol. He died prematurely at Davos, Switzerland, on 23 December 1902 and was buried on Christmas day.