United Kingdom

• John Parker (died 1617) (1548–1617), MP for Truro, Hastings, Launceston and East Looe
• John Parker (died 1619) (1548–1619), MP for Queenborough
• John Parker (MP for Rochester) (fl. 1631–1680), recorder in Kent, MP for Rochester, a judge and a Baron of the Exchequer
• John Parker (MP for Clitheroe) (1754–1797), MP for Clitheroe
• John Parker (cleric) (1798–1860), cleric and artist. Author of "The Passengers: containing the Celtic Annals.", published 1831.
• John Parker (Whig politician) (1799–1881), British politician of the Victorian era, Privy Counsellor, 1853
• John Parker (Labour politician) (1906–1987), British politician, Labour MP for Dagenham, 1945–198
• John Parker, 1st Baron Boringdon (1735–1788), British peer and Member of Parliament
• John Parker, 1st Earl of Morley (1772–1840), British peer and politician
• John Parker, 6th Earl of Morley (1923–2015), British peer

United States

• John Parker (activist), American presidential candidate (2004) of the Workers World Party
• John Parker (Continental Congress) (1759–1832), South Carolina delegate to the Continental Congress, 1786–1788
• John Parker (Montana politician) (born 1970), state representative of Montana
• John Parker (Oswego County, NY) (1810–?), New York assemblyman 1866 and 1870
• John F. Parker (1907–1992), mayor of the city of Taunton, Massachusetts
• John M. Parker (1863–1939), Democratic governor of Louisiana, 1920–1924
• John M. Parker (New York politician) (1805–1873), Congressman from New York
• John J. Parker (1885–1958), failed confirmation to U.S. Supreme Court

Canada

• John Mason Parker (Saskatchewan politician) (1882–1960), politician in Saskatchewan, Canada
• John Parker (Canadian politician) (born 1954), former Ontario MPP and Toronto City Councillor

• John Parker (West Indian cricketer) (1871–1946)
• John Parker (water polo) (born 1946), American water polo player
• John Parker (New Zealand cricketer) (born 1951), New Zealand test cricketer
• John Willie Parker, English former professional footballer
• John Parker (Australian footballer) (born 1971), former Australian rules footballer
• John Parker (English cricketer) (1902–1984), English cricketer, played for Hampshire 1926–29 & 1932–33
• John Parker (Australian cricketer) (born 1936), Australian cricketer
• John Parker (boxer) (born 1994), New Zealand boxer
• John Parker (rower) (born 1967), American rower

• John Parker (Irish judge) (c. 1500–1564), English-born merchant, politician and judge
• John Parker (jurist) (fl. 1655), member of the judiciary during the Interregnum, sat on the High Court of Justice in 1649 that tried Capel, Holland and Hamilton; father of Samuel Parker, Bishop of Oxford
• John Victor Parker (1928–2014), United States federal judge
• John J. Parker (1885–1958), American judge who served at the Nuremberg Trials and missed a nomination to the Supreme Court by one vote

• John Parker (author), British writer
• John Parker (musician), British musician from the band Nizlopi
• John Parker (potter) (born 1947), New Zealand potter
• John Adams Parker (1829–1905), New York painter
• John Henry Parker (1806–1884), English writer on architecture
• Jon Kimura Parker (born 1959), Canadian pianist
• John L. Parker Jr. (born 1947), American writer
• J. S. Parker (1944–2017), New Zealand painter
• John William Parker (1792–1870), English publisher and printer

• John Parker (Jacobite) (c. 1651–in or after 1719), English army officer and Jacobite conspirator
• John Parker (captain) (1729–1775), captain of the Lexington militia at the Battle of Lexington
• John Boteler Parker (1786–1851), English army general
• John