O'Brien, Desmond Joseph ('Des') (1919–2005), rugby player and business executive, was born 22 May 1919 in Dublin, the son of Tim O'Brien and his wife Mary (née Molloy). Educated at Belvedere College (1930–36), he joined Old Belvedere RFC in 1938, playing as flanker on the first two (1939–40, 1940–41) of the renowned Old Belvedere sides that won seven consecutive Leinster Senior Cups in the 1940s. Working for the Guinness company in Park Royal, London, he played two seasons with Wasps RFC during the second world war. Although international competition was suspended during the war, the standard of rugby played in the London area was high, with civilian and military teams peppered with first-class and international players. Joining London Irish RFC (1947–9), he captained them to their most successful season to that date in their fiftieth anniversary season (1948–9). O'Brien won five inter-provincial caps with Leinster from 1947. Moving with Guinness to Wales, he joined Cardiff RFC in 1950–51, a pre-eminent club side who ran South Africa close in October 1951. Although he was already an international, club tradition required him to play his first four games for the reserves. Playing there for two seasons, he declined the Cardiff captaincy and retired from rugby at the end of the 1951–2 season. Joining Cardiff Hockey Club (1952–3), he played for Glamorgan, and was a finalist in the Welsh trials that season.
Making his international rugby debut (aged 28) against England in Twickenham (14 February 1948) in an 11–10 victory, he played no. 8 or flanker alongside Jimmy McCarthy and Bill McKay in a 'devastatingly effective' (Van Esbeck, 112–13), mobile back row whose protective instincts and offensive prowess contributed to Jack Kyle's (qv) shining at out-half. O'Brien's fitness, footballing skills (especially his dribbling off the back of scrums), and reading of the game complemented the speed and agility of McCarthy and McKay. The triumvirate's exemplary fitness was the basis of their dominance as they hunted as a pack, creating space and opportunities in their fourteen consecutive matches together, ten of which they won. O'Brien created the try scored by J. C. Daly in the 6–3 victory over Wales at Ravenhill, Belfast, which secured the 1948 grand slam, Ireland's first triple crown since 1899 and first championship since 1935. 'High jinks' with an Orange flute band that evening resulted in O'Brien and two teammates spending a few hours in police cells. O'Brien was selected for the 1948 Barbarian Easter tour of Wales. The team for the game against Swansea on 29 March comprised ten of that season's Irish team, including O'Brien at no. 8 alongside McKay and McCarthy, in a 12–3 victory.
O'Brien had played in three of the four championship games that season, missing the first fixture, away against France. He played in every championship fixture over the next four seasons (1949–52) as Ireland won the five nations championship and triple crown in 1949, and the championship again in 1951 (their third in four seasons); in the latter, O'Brien's try against Scotland in Murrayfield (his only international try) was essential to the victory. O'Brien's absence from the 1950 British Lions tour to New Zealand aroused considerable comment. O'Brien assumed the Ireland captaincy from Karl Mullen against South Africa in Lansdowne Road (8 December 1951), and retained it for the 1952 five nations campaign. He led the Irish team on a tour of Argentina in 1952 (only the second overseas tour ever undertaken by an Ireland team), arriving in Buenos Aires the day of Eva Peron's death (25 July 1952); the ensuing public mourning and state funeral compelled Ireland to play their first match in Santiago against Chile (a 30–0 victory). Ireland played nine games on the tour (winning six, losing two and drawing one). Playing Argentina twice, they won 6–0 and drew 3–3; caps were not awarded for the games. O'Brien relinquished the captaincy to Jack Kyle in 1952, having won twenty consecutive caps at the heart of a great Irish team. He was a founding member of the Irish Wolfhounds in 1956.
O'Brien also won ten squash caps with Ireland (1952–65), and played competitive tennis with the Kenilworth and Fitzwilliam clubs in Dublin, Cardiff Castle LTC (representing Glamorgan in 1953), and Grange Dyvours LTC in Edinburgh. He played squash with the Grange club in Edinburgh into his 40s. He was once a reserve to the Welsh tennis squad, and regretted never entering Wimbledon as an amateur.
While based near Oxford as a sales manager for Harp Lager, O'Brien was appointed manager of the six-month British Lions tour in 1966 to Australia, New Zealand and Canada, during a transformative period for rugby in Britain and Ireland. The tour was the first to appoint a coach (John Robins), while the selection of England's Michael Campbell-Lamerton as captain, rather than the immense Welshman Alun Pask (who had just led Wales to the five nations championship), was cause for some comment. The absence of clearly delineated authority among manager, coach and captain produced recurring tension and misunderstanding.
After winning their two tests against Australia and completely dominating the regional and club selections they met there (the first Lions tour to leave Australia unbeaten since 1904), they faced formidable opposition and a hostile environment in New Zealand. O'Brien criticised the refereeing and negative rugby the Lions encountered; his assertion, supported by acting captain Jim Telfer, after a loss to Canterbury, that 'we are heartily sick of the obstruction, short-arm tackling and illegal tactics employed by teams we have met in New Zealand' (Times, 3 February 2006), caused a furore, leading to personal mediation between the two sides by the governor general of New Zealand. The New Zealand press sought to exploit divisions in the Lions camp, especially when Campbell-Lamerton was dropped from the test side and the captaincy was deliberately rotated. O'Brien's week-long visit to Fiji on behalf of the Lions Committee to establish closer links with the Pacific nations was wrongly portrayed as his response to undue strain. Losing all four tests in New Zealand, the Lions played British Columbia (losing 3–8) and Canada (winning 19–8) on their westward return home. After the tour, O'Brien's report to the Lions Committee criticised the organisation, selection and length of the tour, as well as the lack of neutral referees and financial support for the touring party.
O'Brien made his working career in the UK as an executive with Guinness, initially in Wales and England before moving to Scotland, where he spent the last forty-five years of his life. Rising to general manager of Guinness (Scotland) by 1970, he later became a director of Harp Lager. He enjoyed his retirement in Edinburgh, taking a master's degree in architectural history at Edinburgh University in his 70s, enjoying poetry and light opera with the Savoy Opera Company, and remaining active in the Grange Hockey Club in Edinburgh into the 1970s. He was inducted into the rugby writers' Irish Hall of Fame in 1991.
O'Brien died 26 December 2005 at his home in Edinburgh, survived by his wife Ann and their daughter and four sons. After a funeral service in Rosewell parish church on the outskirts of Edinburgh, he was buried in Lasswade cemetery, overlooking his home.