• John O'Sullivan (science writer/law advocate) (born 1961), British, coordinator and co-author of 'Slaying the Sky Dragon: Death of the Greenhouse Gas Theory' (2010)
• John O'Sullivan (columnist)
  John O'Sullivan (columnist)
  John O'Sullivan CBE is a leading British conservative political commentator and journalist and currently Vice President and executive editor of Radio Free Europe/Radio Liberty....
  
   (born 1942), British conservative columnist
• John O'Sullivan (rugby union), Irish rugby union footballer
• John L. O'Sullivan
  John L. O'Sullivan
  John Louis O'Sullivan was an American columnist and editor who used the term "Manifest Destiny" in 1845 to promote the annexation of Texas and the Oregon Country to the United States. O'Sullivan was an influential political writer and advocate for the Democratic Party at that time, but he faded...
  
   (1813–1895), journalist who popularized the phrase "Manifest Destiny"
• John M. O'Sullivan
  John M. O'Sullivan
  John M. O'Sullivan was an Irish politician, cabinet minister and academic.John Marcus O'Sullivan was born in Killarney, County Kerry in 1891. He was educated at St. Brendan's, Killarney, Clongowes Wood, Kildare, University College Dublin and the Universities of Bonn and Heidelberg where he was...
  
   (1891–1948), Irish Cumann na nGaedhael/Fine Gael politician, TD, cabinet minister and academic
• John O'Sullivan (Cork politician)
  John O'Sullivan (Cork politician)
  John L. O'Sullivan was an Irish farmer and Fine Gael Party politician from West Cork who was a Senator for 7 years and later a TD for 8 years....
  
   (1901–1990), Irish Fine Gael Party politician, Senator, later TD for Cork South-West
• John Francis O'Sullivan
  John Francis O'Sullivan
  John Francis O'Sullivan was an Irish-born soldier who emigrated to New York City, where he joined the United States Army who served with the 4th U.S. Cavalry during the Texas–Indian Wars...
  
   (1850–1907), Irish-American awarded the Medal of Honor during the Indian Wars

• John O'Sullivan (tenor) (1877-1953?), opera singer
• John O'Sullivan (rugby league), New Zealand rugby league footballer
• John O'Sullivan (engineer), Australian astronomer and electrical engineer
• John O'Sullivan (footballer)
  John O'Sullivan (footballer)
  John O'Sullivan is an Irish professional footballer, who currently plays as a midfielder for Blackburn Rovers F.C.'s reserve team . John is the currently the captain of the Republic of Ireland under-19 football team. in 2010, at age 17, he played for the Irish under-19 team in the European finals...
  
  , Irish footballer playing for Blackburn Rovers F.C.'s academy.

See also

• John Sullivan (disambiguation)
  John Sullivan (disambiguation)
  -In entertainment:* John Sullivan , English writer of screenplays for sitcoms including Only Fools and Horses and Just Good Friends* John Florence Sullivan, also known as Fred Allen, American radio comedian* John L...