John Greer may refer to: John Greer, character in Person of Interest John Greer (American football) (1889–1932), American football coach John Greer (sculptor), Canadian sculptor John Alexander Greer (1802–1855), Texas politician John Allen Greer (1874-1941), Tennessee politician John Michael Greer (born 1962), American author John W. Greer, Jr. (1909–1994), Georgia politician Big John Greer (1923–1972), American blues singer