| 45991 | April 21 | Birth | 1889 – Efrem Zimbalist, Russian-American violinist, composer, and conductor (d. 1985) |
| 45992 | April 21 | Birth | 1890 – Marc Wright, American pole vaulter (d. 1975) |
| 45993 | April 21 | Birth | 1892 – Freddie Dixon, English motorcycle racer and racing driver (d. 1956) |
| 45994 | April 21 | Birth | 1893 – Romeo Bertini, Italian runner (d. 1973) |
| 45995 | April 21 | Birth | 1898 – Maurice Wilson, English soldier, pilot, and mountaineer (d. 1934) |
| 45996 | April 21 | Birth | 1899 – Randall Thompson, American composer and academic (d. 1984) |
| 45997 | April 21 | Birth | 1903 – Issy Bonn, English actor and singer (d. 1977) |
| 45998 | April 21 | Birth | 1903 – Luis Saslavsky, Argentinian director, producer, and screenwriter (d. 1995) |
| 45999 | April 21 | Birth | 1904 – Odilo Globocnik, Italian-Austrian SS officer (d. 1945) |
| 46000 | April 21 | Birth | 1905 – Pat Brown, American lawyer and politician, 32nd Governor of California (d. 1996) |
| 46001 | April 21 | Birth | 1906 – Eugen Sacharias, German-Estonian architect (d. 2002) |
| 46002 | April 21 | Birth | 1907 – Wade Mainer, American singer and banjo player (d. 2011) |
| 46003 | April 21 | Birth | 1911 – Ivan Combe, American businessman, developed Clearasil (d. 2000) |
| 46004 | April 21 | Birth | 1911 – Leonard Warren, American opera singer (d. 1960) |
| 46005 | April 21 | Birth | 1912 – Marcel Camus, French director and screenwriter (d. 1982) |
| 46006 | April 21 | Birth | 1913 – Norman Parkinson, English photographer (d. 1990) |
| 46007 | April 21 | Birth | 1914 – Norman Panama, American director and screenwriter (d. 2003) |
| 46008 | April 21 | Birth | 1914 – Angelo Savoldi, Italian-American wrestler and promoter, co-founded International World Class Championship Wrestling (d. 2013) |
| 46009 | April 21 | Birth | 1915 – Garrett Hardin, American ecologist, author, and academic (d. 2003) |
| 46010 | April 21 | Birth | 1915 – Anthony Quinn, Mexican-American actor and producer (d. 2001) |
| 46011 | April 21 | Birth | 1916 – Estella B. Diggs, American businesswoman and politician (d. 2013) |
| 46012 | April 21 | Birth | 1916 – Eldon Rathburn, Canadian composer (d. 2008) |
| 46013 | April 21 | Birth | 1918 – Eddy Christiani, Dutch singer-songwriter and guitarist |
| 46014 | April 21 | Birth | 1919 – Don Cornell, American singer and trumpet player (d. 2004) |
| 46015 | April 21 | Birth | 1919 – Roger Doucet, Canadian tenor (d. 1981) |
| 46016 | April 21 | Birth | 1920 – Edmund Adamkiewicz, German footballer (d. 1991) |
| 46017 | April 21 | Birth | 1920 – Ronald Magill, English actor (d. 2007) |
| 46018 | April 21 | Birth | 1922 – Nazim Al-Haqqani, Cypriot sufi leader (d. 2014) |
| 46019 | April 21 | Birth | 1922 – Alistair MacLean, Scottish-Swiss author and screenwriter (d. 1987) |
| 46020 | April 21 | Birth | 1923 – John Mortimer, English lawyer and author (d. 2009) |