John O'Brien may refer to: Public officials American John O'Brien (Ohio politician) (1932–1985), former member of the Ohio House of Representatives John D. O'Brien, state senator in the 1997–1998 Massachusetts legislature John F. O'Brien (secretary of state) (c. 1850–1927), Secretary of State of New York, 1903–1906 John F. O'Brien (judge) (1874–1939), New York Court of Appeals judge John H. O'Brien, 4th Fire Commissioner of the City of New York John J. O'Brien (civil servant) (1919–2001), investigated the assassination of President John F. Kennedy John J. O'Brien (commissioner), former commissioner of the Massachusetts Probation Service John P. O'Brien (1873–1951), 98th mayor of New York City John L. O'Brien (1911–2007), American politician in the Washington House of Representatives Irish John O'Brien (bishop) (died 1767), Irish Bishop of Cork and Cloyne John O'Brien (Irish politician) (1794–1855), MP for Limerick City in the UK Parliament 1841–1852 John O'Brien (priest) (1931–2008), Irish Roman Catholic priest and musician John Thomond O'Brien (1786–1861), Irish soldier in the Argentine War of Independence British John O'Brien (British politician) (died 1982), far right figure, onetime leader of the British National Front Sir Terence O'Brien (colonial administrator) (John Terence Nicholls O'Brien, 1830–1904), British surveyor, engineer and colonial governor Canadian John O'Brien (admiral) (1918–1996), commander of the Royal Canadian Navy John O'Brien (Canadian politician) (1847–1917), merchant and member of the Legislative Assembly of New Brunswick New Zealand John O'Brien (New Zealand politician) (1925–1990), New Zealand political candidate and party leader Australian John O'Brien (Australian politician) (1866–1932), Member of the Queensland Legislative Assembly John O'Brien (Australian Army officer) (1908–1980), Australian major general and Mayor of Woollahra Sportspeople Baseball John O'Brien (outfielder) (1851–1914), baseball outfielder John O'Brien (second baseman) (1866–1913), baseball infielder Johnny O'Brien (born 1930), 1950's baseball second baseman Cinders O'Brien (John F. O'Brien, 1867–1892), baseball pitcher Footballers John O'Brien (Dublin footballer), senior inter-county Gaelic footballer for Dublin and Round Towers, Clondalkin John O'Brien (Louth footballer) (born 1985), Gaelic footballer for Louth John O'Brien (soccer) (born 1977), American soccer player Jon O'Brien (born 1961), English footballer Other sports John O'Brien (basketball, born 1888) (1888–1967), American basketball referee and executive John O'Brien (basketball, born 1916) (1916–1994), American professional basketball player in the 1940s John O'Brien (boxer) (1937–1979), Scottish boxer of the 1960s and '70s John O'Brien (cricketer, born 1961), English cricketer John O'Brien (Irish cricketer) (1866–1920), Irish cricketer John O'Brien (hurler) (born 1982), Irish hurler John O'Brien (rower) (1927–1995), New Zealand representative rower John