John: The narrator of the novel. The opening "Call me Jonah" suggests a parallel to Ishmael, the narrator of Moby-Dick, and also to the Biblical Jonah.
Dr. Felix Hoenikker: An evil scientist who developed the atom bomb.
Franklin Hoenikker: Dr. Hoenikker's son.
Angela Hoenikker: Dr. Hoenikker's daughter. Very tall and extremely ugly.
Newt Hoenikker: Dr. Hoenikker's son: A dwarf who had an affair with a Russian midget.
Dr. Asa Breed: scientist, once boss of Dr. Felix Hoenikker. Ignores moral implications of his own work.
Papa Monzano: San Lorenzo's dictator,
Lionel Boyd Johnson: Based on the US President Lyndon B. Johnson.
H. Lowe Crosby and his wife, Hazel. American business people.
Earl McCabe and Bokonon: Founders of Lorenzo.
Mona: Monzano’s adopted daughter.