Namesakes
Bulgarian Presidents and Prime Ministers:
1 prime minister
(prime minister) John Casimir Ehrnrooth 1881 
French Presidents and Prime Ministers:
2 prime ministers
(prime minister) Casimir Pierre Périer 1831-1832
(prime minister) Édouard Mortier, duc de Trévise (middle name Casimir) 1834-1835
Most Valuable Players:
1 winner
Jim Konstanty (a.k.a. Casimir) 1950 baseball
Notable Military Figures:
1 general
Kazimierz Pułaski (a.k.a. Casimir) 1745-1779
Olympic Medalists:
1 silver
(silver) Charles Poulenard (middle name Casimir) 1912 4x400 m relay
Other Royalty:
1 prince
Ernst Casimir of the Netherlands 1822 Netherlands
Polish High Dukes and Kings:
2 dukes, 2 kings
Duke Kazimierz I the Restorer (a.k.a. Casimir) 1040-1058
Duke Kazimierz II the Just (a.k.a. Casimir) 1177-1191; 1191-1194
King Kazimierz III the Great (a.k.a. Casimir) 1333-1370
King Kazimierz IV (a.k.a. Casimir) 1447-1492
Saints:
1 saint
Saint Kazimierz of Poland (a.k.a. Casimir) 1458-1484