Authors Born on April 21
- James Martineau Philosopher, 1805
- James McAvoy Actor, 1979
- Janine di Giovanni Author, 0
- Jean-Pierre Dardenne Film Maker, 1951
- Jeannette Walls Author, 1960
- Jencarlos Canela Singer-Songwriter, 1988
- Jerry Only Musician, 1959
- Jessica Clark Actress, 1985
- Jodi Kantor Journalist, 1975
- John Cameron Mitchell Actor, 1963
- John Mortimer Barrister, 1923
- John Muir Naturalist, 1838
- Josh Billings Writer, 1818
- Jukka Nevalainen Drummer, 1978
- Katsura Hoshino Mangaka, 1980
- Ken Caminiti Athlete, 1963
- Lemon Andersen Poet, 1975
- Luke Harding Journalist, 1968
- Max Weber Sociologist, 1864
- Michael Franti Musician, 1967
- Molly Bloom Entrepreneur, 1978
- Morgan Wootten Basketball Coach, 1931
- Nicole Sullivan Actress, 1970
- Norman Parkinson Photographer, 1913
- Odilo Globocnik Criminal, 1904
- Pat Brown Lawyer, 1905
- Patti LuPone Actress, 1949
- Queen Elizabeth II Royalty, 1926
- Robert Smith Musician, 1959
- Rollo May Psychologist, 1909
- Sergey Brin Businessman, 1973
- Sydney Sierota Lead Vocalist, 1997
- Tarvaris Jackson American Football Player, 1983
- Tavi Gevinson Journalist, 1996
- Terrence J Actor, 1982
- Tim Leiweke Businessman, 1957
- Toby Stephens Actor, 1969
- Tony Danza Actor, 1951
- William Lee Miller Journalist, 1926