Namesakes
Belgian Prime Ministers:
2 prime ministers
Georges Theunis (middle name Léonard) 1921-1925; 1934-1935 
Leo Tindemans 1974-1978
British Prime Ministers:
1 prime minister
James Callaghan (a.k.a. Leonard) 1976-1979
Dutch Prime Ministers:
1 prime minister
Justinus van der Brugghen (middle name Leonard) 1856-1858
Fictional Characters from Books:
1 character
Leonard Peacock 2013 Forgive Me, Leonard Peacock
Fictional Characters from Song Titles:
2 characters
(character) Leonard 1980 Leonard
(character) Leonard 2012 Leonard
Fictional Characters from Television:
6 characters
Leonard "Bones" McCoy 1966 Star Trek
Leonard Waggedorn 1968 Julia
Lennie Briscoe (a.k.a. Leonard) 1990 Law & Order
Leo Chingkwake 1998 That '70s Show
Stan Smith (middle name Leonard) 2005 American Dad!
Leonard Hofstadter 2007 The Big Bang Theory
French Presidents and Prime Ministers:
1 prime minister
(prime minister) Léon Faucher 1851
Hall-of-Famers:
3 football, 1 basketball, 1 ice hockey
(ice hockey) Leonard "Red" Kelly 1969
(football) Lenny Moore 1975
(football) Len Ford 1976
(football) Len Dawson 1987
(basketball) Lenny Wilkens 1989; 1998
Nobel Prize Winners:
1 medicine, 1 physics
(physics) Arthur Leonard Schawlow 1981
(medicine) Gregg L. Semenza (middle name Leonard) 2019
Notable Actors and Entertainers:
12 actors, 1 comedian
Canada Lee (a.k.a. Leonard) 1907-1952
Buddy Hackett (a.k.a. Leonard) 1924-2003
Lenny Bruce 1925-1966
Leonard Nimoy 1931-2015
Leonard Frey 1938-1988
Len Cariou 1939-
Barry Corbin (a.k.a. Leonard) 1940-
Gareth Hunt (middle name Leonard) 1942-2007
Timothy Dalton (middle name Leonard) 1946-
Ed O'Neill (middle name Leonard) 1946-
Timothy Spall (middle name Leonard) 1957-
Adrian Lukis (middle name Leonard) 1957-
Joseph Gordon-Levitt (middle name Leonard) 1981-
Notable Athletes:
2 soccer, 1 basketball, 1 football, 1 ice hockey
(ice hockey) Leonard "Red" Kelly 1927-2019
(soccer) Leo Canjels 1933-2010
(football) Len Dawson 1935-2022
(basketball) Lenny Wilkens 1937-
(soccer) Jairo Patiño (middle name Leonard) 1978-
Notable Businesspeople:
1 businessperson
Jack L. Warner (middle name Leonard) 1892-1978
Notable Filmmakers:
1 director
Lenny Abrahamson 1966-
Notable Musicians:
3 musicians, 1 composer, 1 singer
Leonard Bernstein 1918-1990
Lennie Niehaus 1929-2020
Leonard Cohen 1934-2016
Lenny Kravitz 1964-
Big Sean (middle name Leonard) 1988-
Notable Scientists and Inventors:
2 physicists
Nicolas Léonard Sadi Carnot 1796-1832
Arthur Leonard Schawlow 1921-1999
Notable Writers:
1 author
Eckhart Tolle (middle name Leonard) 1948-
Olympic Medalists:
1 bronze, 1 silver
(bronze) Jimmy Tremeer (a.k.a. Leonard) 1908 400 m hurdles
(silver) Leon Gregory 1956 4x400 m relay
Rock and Roll Hall-of-Famers:
3 musicians
Leonard Cohen 2008
Lenny Davidson 2008 The Dave Clark Five
Jonathan Cain (middle name Leonard) 2017 Journey
Saints:
4 saints, 1 blessed
Saint Leonard of Noblac ?-559
Saint Leonard of Vandoeuvre ?-570
Saint Leonardus van Veghel (a.k.a. Leonard) ?-1572
Blessed Leonard Kimura ?-1619
Saint Leonardo of Porto Maurizio (a.k.a. Leonard) 1676-1751
Swedish Prime Ministers:
1 prime minister
Hjalmar Hammarskjöld (middle name Leonard) 1914-1917