- Apr 1 Trial begins in Budapest against participants october uprising
- Apr 1 WYES TV channel 12 in New Orleans, LA (PBS) begins broadcasting
- Apr 1 World's biggest glass oven used
Event of Interest
Apr 3 Samuel Beckett's "Endgame" premieres in London

Samuel Beckett
- Apr 3 USSR performs atmospheric nuclear test
- Apr 4 Heitor Villa-Lobos' 10th Symphony premieres French Radio National Orchestra, conducted by the composer, in Paris
- Apr 6 NYC ends trolley car service
- Apr 6 USSR performs nuclear test (atmospheric tests)
- Apr 6 Greek shipping tycoon Aristotle Onassis buys the Hellenic National Airlines (TAE) and founds Olympic Airlines.
US Masters Golf
Apr 7 21st US Masters Tournament, Augusta National GC: Doug Ford wins his only Masters, 3 strokes ahead of 3-time champion Sam Snead

Sam Snead
- Apr 7 Last of NY's electric trolleys completes its final run
Event of Interest
Apr 9 Howard Hanson's "Song of Democracy" premieres in Washington, D.C.

Howard Hanson
Film Release
Apr 10 "12 Angry Men", directed by Sidney Lumet, starring Henry Fonda and Lee J. Cobb, is released

Henry Fonda
Event of Interest
Apr 11 Pablo Neruda arrested in Buenos Aires

Pablo Neruda
- Apr 11 Ryan X-13 Vertijet becomes 1st jet to take-off & land vertically
- Apr 11 Britain agrees to Singaporean self-rule.
- Apr 12 Jim Spalding set a 2,088 pin nine-game bowling record
- Apr 12 USSR performs atmospheric nuclear test
- Apr 13 "Shinbone Alley" opens at Broadway Theater NYC for 49 performances
- Apr 13 11th NBA Championship: Bost Celtics beat St Louis Hawks, 4 games to 3
- Apr 13 11th Tony Awards: "Long Days Journey into the Night" & "My Fair Lady" win
- Apr 13 Saturday postal delivery in US is temporarily halted due to lack of funds
- Apr 14 Leah Neuberger wins her 8th women's singles ping pong championship
- Apr 15 KTVI TV channel 2 in Saint Louis, MO (ABC) begins broadcasting
- Apr 15 Saturday mail delivery restored in the US after Congress gives the Post Office $41 million
- Apr 15 61st Boston Marathon won by John J Kelley in 2:20:05; course length changed
- Apr 16 Stanley Cup Final, Montreal Forum, Montreal, Quebec: Dickie Moore has a goal and 2 assists as Montreal Canadiens beat Boston Bruins, 5-1 for a 4-1 series victory
- Apr 16 USSR performs atmospheric nuclear test
- Apr 20 Yankee Bill Skowron becomes 3rd player to hit a ball out of Fenway
- Apr 22 All NL baseball teams integrate, John Irwin Kennedy becomes the 1st Black player for the Philadelphia Phillies
- Apr 24 Chicago Cub pitchers walk NL record 9 Reds in 5th inning
- Apr 25 1st experimental sodium nuclear reactor operated
- Apr 25 Ibrahim Hashim forms Jordanian government
- Apr 25 WUHY TV channel 35 in Philadelphia, PA (PBS) begins broadcasting
- Apr 26 Jamestown, Virginia 350th Anniversary Festival opens
- Apr 28 LPGA Western Open Women's Golf, Montgomery CC: Patty Berg wins her 6th WO by 1 stroke from Wiffi Smith
- Apr 28 WSOC TV channel 9 in Charlotte, North Carolina (ABC) begins broadcasting
- Apr 28 4th National Film Awards (India): "Kabuliwala" wins the Golden Lotus
- Apr 29 1st military nuclear power plant dedicated at Fort Belvoir, Virginia