Namesakes
Belgian Prime Ministers:
1 prime minister
Leo Tindemans 1974-1978 
Bishops of Rome and the Popes:
13 popes
Leo I the Great 440-461
Leo II 682-683
Leo III 795-816
Leo IV 847-855
Leo V 903
Leo VI 928
Leo VII 936-939
Leo VIII 964-965
Leo IX 1049-1054
Leo X 1513-1521
Leo XI 1605
Leo XII 1823-1829
Leo XIII 1878-1903
Characters in Greek Mythology:
1 character
Leo (m)
Fictional Characters from Television:
5 characters, 1 hero
Leo Dalton 1996 Silent Witness
Leo Chingkwake 1998 That '70s Show
Leo Markus 1998 Will & Grace
Leo Wyatt 1998 Charmed
Leo Fisher 1999 Once and Again
Leo Mason 2012 Major Crimes
German Chancellors and Presidents:
1 chancellor
(chancellor) Leo von Caprivi 1890-1894
Hall-of-Famers:
2 baseball, 1 football, 1 ice hockey
(baseball) Gabby Hartnett (a.k.a. Leo) 1955
(football) Leo Nomellini 1969
(ice hockey) Leo Boivin 1986
(baseball) Leo Durocher 1994
Irish Presidents and Prime Ministers:
1 prime minister
(prime minister) Leo Varadkar 2017-2020; 2022-2024
Most Valuable Players:
1 winner
Gabby Hartnett (a.k.a. Leo) 1935 baseball
Nobel Prize Winners:
1 physics
(physics) Reona Esaki (a.k.a. Leo) 1973
Notable Actors and Entertainers:
8 actors
Leo Carrillo 1880-1961
Leo G. Carroll 1886-1972
Leo Genn 1905-1978
Lee J. Cobb (a.k.a. Leo) 1911-1976
Leo McKern 1920-2002
Branscombe Richmond (a.k.a. Leo) 1955-
Taye Diggs (a.k.a. Leo) 1971-
Leo Howard 1997-
Notable Athletes:
1 ice hockey, 1 soccer
(ice hockey) Leo Boivin 1931-2021
(soccer) Leo Canjels 1933-2010
Notable Businesspeople:
1 businessperson
Leo Fender 1909-1991
Notable Filmmakers:
2 directors
Leo McCarey 1898-1969
Joseph L. Mankiewicz (a.k.a. Leo) 1909-1993
Notable Musicians:
2 singers, 1 composer, 1 musician
Léo Delibes 1836-1891
Johnny Hallyday (a.k.a. Léo) 1943-2017
Leo Sayer 1948-
Norman "Fatboy Slim" Cook (a.k.a. Leo) 1963-
Notable Scientists and Inventors:
1 inventor, 1 physicist
Leo Fender 1909-1991
Reona Esaki (a.k.a. Leo) 1925-
Notable Writers:
1 author
Leo Tolstoy 1828-1910
Olympic Medalists:
5 bronze, 3 silver, 2 gold/bronze, 1 gold, 1 silver/bronze
(gold/bronze) Leo Goodwin 1904; 1908 diving - plunge for distance; swimming - 4x50 yard freestyle relay; water polo; swimming - 4x200 m freestyle relay
(bronze) Leo Larrivee 1924 3000 m team
(gold) Leo Sexton 1932 shot put
(bronze) James Dillion (a.k.a. Leo) 1952 discus throw
(bronze) Veikko Karvonen (a.k.a. Leo) 1956 marathon
(bronze) Leonhard Pohl (a.k.a. Leo) 1956 4x100 m relay
(silver) Benny Nielsen (a.k.a. Leo) 1988 swimming - 200 m butterfly
(silver/bronze) Leo Visser 1988; 1992 speed skating
(silver) Leo Peelen 1988 cycling - track
(gold/bronze) Leonardo Gutiérrez (a.k.a. Leo) 2004; 2008 basketball
(silver) Leonel Manzano (a.k.a. Leo) 2012 1500 m
(bronze) Leo Komarov 2014 ice hockey
Oscar Award Winners:
2 directors
(director) Leo McCarey 1938; 1945 The Awful Truth; Going My Way
(director) Joseph L. Mankiewicz (a.k.a. Leo) 1950; 1951 A Letter to Three Wives; All About Eve
Other Leaders:
1 president
President Leo Falcam 1999-2003 Federated States of Micronesia
Roman and Byzantine Emperors:
7 emperors
Emperor Flavius Valerius Leo (a.k.a. Leo) 457-474
Emperor Flavius Leo Junior (a.k.a. Leo) 474
Emperor Leo 695-698
Emperor Leo 717-741
Emperor Leo 775-780
Emperor Leo 813-820
Emperor Leo 886-912
Saints:
17 saints, 5 blessed
Saint Leo ?-260
Saint Leo the Great c. 400-461
Saint Leo ?-541
Saint Leo ?-550
Saint Leo II 611-683
Saint Leo III 750-816
Saint Leo ?-787
Saint Leo IV 790-855
Saint Leo of Carentan 856-890
Saint Leo Luke ?-900
Saint Leo ?-900
Saint Leo of Nonantula ?-1000
Saint Leo IX 1002-1054
Saint Leo of Lucca ?-1079
Blessed Leo of Saint-Bertin ?-1163
Saint Leo Karasuma ?-1597
Saint Leo Tanaka ?-1617
Blessed Leo Nakanishi ?-1619
Saint Leo Satsuma ?-1622
Blessed Leo Suchiemon ?-1622
Blessed Leo Kombiogi ?-1628
Blessed Leo Ignatius Mangin ?-1900