JOHNNY TARLETON: "an ordinary young business man of thirty or less," son of John Tarleton, Sr., working his way into his father's underwear business
JOHN TARLETON, SR.: father of Johnny and Hypatia Tarleton, "has made a great deal of money out of Tarleton's Underwear," a great supporter of "free libraries."
BENTLEY SUMMERHAYS: son of Lord Summerhays, fiancee of Hypatia, great annoyance to Johnny, "one of those smallish, thin-skinned youths, who from 17 to 70 retain unaltered the mental airs of the latter and the physical appearance of the earlier age"
LORD SUMMERHAYS: a former colonial governor, father of Bentley, at on time proposed to Hypatia, a very proper Englishman
HYPATIA: daughter of John Tarleton, fiance of Bentley, "a typical English girl of a sort never called typical: this is, she has an opaque white skin, black hair, large dark eyes with black brows and lashes, curved lips, swift glances and movements that flash out of a waving stillness, boundless energy, and audacity held in leash"
MRS. TARLETON: wife of John Tarleton and mother of Johnny and Hypatia; "shrewd and motherly old lady who has been pretty in her time, and is still very pleasant and likeable and unaffected"
JOEY PERCIVAL: friend of Bentley and part-time aviator, a splendid specimen of humanity, later courts Hypatia
LINA SZCZEPANOWSKA: member of a famous Polish family of acrobats who make it a point of honor to risk their lives at least once a day; receives proposals from Johnny, Mr. Tarleton, and Lord Summerhays, but later pairs off with Bentley
JULIUS BAKER ("GUNNER"): a peculiar young man who accuses Mr. Tarleton at gunpoint of, years ago, seducing and abandoning his mother, Mrs. Tarleton later takes him under her wing