There are a large number of celebrities (mostly in sports) with this name.
(see the related question)
John Jeremiah Sullivan (writer) will be 44 years old in 2018 (born 1974).
John William Sullivan (Australian politician) is 89 years old (birthdate February 7, 1929).
John A. Sullivan (US politician) is 53 years old (birthdate: January 1, 1965).
Athletes:
Jonathan D. Sullivan (footballer) is 30 years old (birthdate: March 8, 1988).
John Sullivan (Irish footballer) is 27 years old (birthdate: January 6, 1991).
John Sullivan (ex-cricketer) is 70 years old (birthdate: March 11, 1948).
John Sullivan (Canadian footballer) is 36 years old (birthdate: July 28, 1981).
John Sullivan (NFL player) is 32 years old (birthdate: August 8, 1985).
John Lloyd Sullivan (ex-NFL) is 36 years old (birthdate: November 15, 1981).
John Sullivan (tennis player) is 51 years old (birthdate: December 22, 1966).
John Sullivan (English ex-cricketer) was 61 years old when he died on February 22, 2006 (birthdate: February 5, 1945).
Others:
UK author John Richard Thomas Sullivan died at the age of 64 on April 23, 2011.
(birthdate: December 23, 1946)
Wrestler and manager John L. Sullivan, aka Johnny Valiant, was 71 years old when he died on April 4, 2018 (born Thomas Sullivan, November 26, 1946).
John Joseph Sullivan (US lawyer) is 58 years old (birthdate November 20, 1959).
John Sullivan was born on January 1, 1965.
John Sullivan was born on January 1, 1965.
John Sullivan - writer - died on 2011-04-23.
John Alexander Sullivan died on 1952-08-11.
John Joseph Sullivan (US lawyer) is 58 years old (birthdate November 20, 1959).
John L. Sullivan was born on October 15, 1858 and died on February 2, 1918. John L. Sullivan would have been 59 years old at the time of death or 156 years old today.
John Sullivan died in 1795.
John Jeremiah Sullivan was born in 1974.
John C. Sullivan died in 1830.
John Sullivan House was created in 1764.
John B. Sullivan died in 1951.
John B. Sullivan was born in 1897.
John Parker Sullivan is 6' 1".
NFL player John Sullivan is 6'-04''.
John Sullivan was born on January 1, 1965.
John Sullivan was born on January 1, 1965.