Martin Arrowsmith
The novel’s protagonist and titular figure is a medical doctor with a strong bent toward the research side of the industry that is only stoked by the influence of Dr. Gottlieb. He is the American Dream come true; a man of humble origins who wills himself to success throughout the long trek from undergraduate studies through medical school and into the wealth that being a doctor brings. Something vital is missing, however, and that gap pushes Arrowsmith inexorably toward the wilds of Vermont in a noble pursuit of purity of purpose within the scientific branch of medicine.
Max Gottlieb
Professor of bacteriology who comes under fire from the less scientifically inclined and progressive minds within the world of medicine for pursuing ideas considered eccentric at best. His influence upon Arrowsmith runs deep and eventually he is able to rise above his critics to be appointed director of the McGurk Institute of Biology. Arrowsmith particularly falls under the spell of Gottlieb’s demonstration that one can pursue a career in science—and even medicine—without necessarily being terribly concerned with its practical consequences in the real world.
Madeline Fox
Arrowsmith is not just about medicine, science, corruption and ethics; it is also a love story of sorts. The first woman under whose spell the relatively unsophisticated Arrowsmith falls is a graduate student pursuing a degree in English. Martin is not quite educated enough at this point to recognize that what seems to be intelligence is actually pretension and so Madeline briefly becomes his fiancé.
Leora Tozer
After his engagement with Madeline falls through, Arrowsmith makes Leora his wife while he is still a medical student. She lacks even the pretension toward intelligence exhibited by Madeline, but possesses a much truer heart. Her own pursuit of a career in nursing will result in an ironic end when she succumbs to the bubonic plague.
Joyce Lanyon
The search for love continues for Arrowsmith from Leora to a wealth woman who has been widowed like Martin. The marriage is not destined for a happy for ever after because she finds her new husband to somehow be both crude and uncultivated at the same time he is woefully idealistic about his medical research.
Terry Wickett
By the time Arrowsmith actually arrives at the McGurk Institute, a researcher there named Terry Wickett has already become cynical and obnoxious. Although these qualities has the immediate effect of putting Arrowsmith off Wickett, eventually their shared interest in pursuing pure research creates a bond that ultimately leads to their dream come true: a private institute for scientific research existing independent of the corrupting influences that has led to Wickett’s cynicism and Arrowsmith’s willingness to sacrifice all the ignoble yet deeply desirous benefits that seems to him to be the primary forces driving most people to go into medicine in the first place.
