Hugh Akston is identified as "One of the last great advocates of reason." He was a renowned philosopher and the head of the Department of Philosophy at Patrick Henry University, where he taught Francisco d'Anconia, John Galt, and Ragnar Danneskjöld. He was, along with Robert Stadler, a father figure to these three. Akston's name is so hallowed that a young lady, on hearing that Francisco had studied under him, is shocked. She thought he must have been one of those great names from an earlier century. He now works as a cook in a roadside diner, and proves extremely skillful at the job. When Dagny tracks him down, and before she discovers his true identity, he rejects her enthusiastic offer to manage the dining car services for Taggart Transcontinental. He is based on Aristotle.
Jeff Allen is a tramp who stows away on a Taggart train during one of Dagny's cross-country trips. Instead of throwing him out, she allows him to ride as her guest. It is from Allen that she learns the full story behind the collapse of the Twentieth Century Motor Company (Rand's extensive metaphor for the inherent flaws of communism), as well as a hint of John Galt's true background.
Calvin Atwood is owner of Atwood Light and Power Company and joins Galt's strike.
Mayor Bascom is the mayor of Rome, Wisconsin, who reveals part of the history of the Twentieth Century Motor Company.
Dr. Blodgett is the scientist who pulls the lever to demonstrate Project X.
Orren Boyle is the head of Associated Steel, antithesis of Hank Rearden and a friend of James Taggart. He is an investor in the San Sebastián Mines. He disappears from the story after having a nervous breakdown following the failed 'unification' of the steel industry.
Laura Bradford is an actress and Kip Chalmers' mistress. She is one of the passengers on his train, and dies in the Taggart Tunnel disaster.
Bill Brent is the chief dispatcher for the Colorado Division of Taggart Transcontinental, who tries to prevent the Taggart Tunnel disaster.
Cherryl Brooks is a dime store shopgirl who marries James Taggart after a chance encounter in her store the night the John Galt Line was falsely deemed his greatest success. She marries him thinking he is the heroic person behind Taggart Transcontinental. Cherryl is at first harsh towards Dagny, having believed Jim Taggart's descriptions of his sister, until she questions employees of the railroad. Upon learning that her scorn had been misdirected, Cherryl puts off apologizing to Dagny out of shame, but eventually admits to Dagny that when she married Jim, she thought he had the heroic qualities that she had looked up to - she thought she was marrying someone like Dagny. Shortly after making this admission, she commits suicide by jumping over a stone parapet and into the river, unable to live with her evil husband and seeing no way to escape him.
Emma Chalmers, Kip Chalmers' mother, gains some influence after his death. Known as "Kip's Ma," she starts a soybean-growing project in Louisiana and commandeers thousands of railroad freight cars to move the harvest. As a result, the year's wheat crop from Minnesota never reaches the rest of the country, but instead rots in storage; also, the soybean crop is lost, having been reaped too early.
Kip Chalmers is a Washington man who has decided to run for election as Legislator from California. On the way to a campaign rally, the Taggart Transcontinental train that is carrying him encounters a split rail, resulting in the destruction of its diesel engine. His demands lead to a coal-burning steam engine being attached to his train in its stead and used to pull it through an eight-mile tunnel. The result is the suffocation of all passengers and the destruction of the Taggart Tunnel.
Tom Colby is the head of the Rearden Steel Workers Union.
Dan Conway is the middle-aged president of the Phoenix-Durango railroad. Running a railroad is just about the only thing he knows. When the Anti-dog-eat-dog Rule is used to drive his business out of Colorado, he loses the will to fight, and resigns himself to a quiet life of books and fishing. He is not one of those who joined John Galt's strike, his resignation being a personal choice of his own.
Ken Danagger owns Danagger Coal in Pennsylvania. He helps Hank Rearden illegally make Rearden Metal, then later decides to quit and join Galt's strike moments before Dagny arrives to try to persuade him otherwise.
Quentin Daniels is an enterprising engineer hired by Dagny Taggart to reconstruct John Galt's motor. Partway through this process, Quentin withdraws his effort for the same reasons John Galt himself had. Dagny's pursuit of Quentin leads her to Galt's Gulch. Galt recognizes in him a younger version of himself, having emulated both Galt's achievements in physics and Galt's social reasoning.
Balph Eubank is called "the literary leader of the age", despite the fact that no book he has written has sold more than 3,000 copies. He complains that it is disgraceful that artists are treated as peddlers, and that there should be a law limiting the sales of books to 10,000 copies. He is a misogynist who thinks it disgusting that Dagny Taggart is a railroad vice-president.
The Fishwife is one of the strikers, who earns her living by providing the fish for Hammond's grocery market; she is described as having "dark, disheveled hair and large eyes", and is a writer. Galt says she "wouldn't be published outside. She believes that when one deals with words, one deals with the mind." This character represents Rand herself; it is her cameo appearance in her own novel.
Richard Halley is Dagny Taggart's favorite composer, who mysteriously disappeared after the evening of his greatest triumph. Halley spent years as a struggling and unappreciated composer. At age 24, his opera Phaethon was performed for the first time, to an audience who booed and heckled it. After 19 years, Phaethon was performed again, but this time it was received to the greatest ovation the opera house had ever heard. The following day, Halley retired, sold the rights to his music, and disappeared. It is later revealed that he has joined the strike and settled in Galt's Gulch.
Lawrence Hammond runs Hammond Cars in Colorado, one of the few companies in existence that still produces top-quality vehicles. He eventually quits and joins the strike.
Mrs. William Hastings is the widow of the chief engineer at the Twentieth Century Motor Company. Her husband quit shortly after Galt did and joined the strike some years later. Her lead allows Dagny to find Hugh Akston.
Dr. Thomas Hendricks is a famous brain surgeon who developed a new method of preventing strokes. He joined Galt's strike when the American medical system was put under government control.
Tinky Holloway is one of the "looters" and is frequently referred to and quoted by other characters in the story, but he has only one major appearance: during the Washington meeting with Hank Rearden.
Lee Hunsacker is in charge of a company called Amalgamated Service that takes over the Twentieth Century Motor Company. He files a lawsuit that eventually leads to Midas Mulligan and Judge Narragansett joining the strike. A failed businessman, he laments constantly that no-one ever gave him a chance.
Gwen Ives is Hank Rearden's secretary, described as being in her late twenties and remaining calm and professional despite the chaos that threatens his business. When Rearden abandons his mills and joins Galt's strike, she and many other employees do the same.
Gilbert Keith-Worthing is a British novelist of erstwhile fame, now neglected but still considered a "walking classic," and a proponent of the idea that freedom is an illusion. Kip Chalmers brings him along on the train to California, "for no reason that either of them could discover"; he dies in the Taggart Tunnel disaster.
Owen Kellogg is Assistant to the Manager of the Taggart Terminal in New York. He catches Dagny Taggart's eye as one of the few competent men on staff. After seeing the sorry state of the Ohio Division, she decides to make him its new Superintendent. However, as soon as she returns to New York, Kellogg informs her that he is quitting his job. Owen Kellogg eventually reaches, and settles in, Galt's Gulch.
Fred Kinnan is a labor leader and member of the looter cabal. Unlike the others, however, Kinnan is straightforward and honest about his purpose. Kinnan is the only one to openly state the true motivations of himself and his fellow conspirators. At the end of Galt's three-hour speech, he expresses admiration for the man, as he says what he means. Despite this, Kinnan admits that he is one of the people Galt is out to destroy.
Paul Larkin is an unsuccessful, middle-aged businessman, a friend of the Rearden family. He meets with the other Looters to work out a plan to bring Rearden down. James Taggart knows he is friends with Hank Rearden and challenges his loyalty, and Larkin assures Taggart that he will go along with them.
Eugene Lawson heads the Community Bank of Madison, then gets a job with the government when his bank goes bankrupt due to new government policies. One of the looter's cabal, he is a collectivist who abhors production and money-making.
Mort Liddy is a hack composer who writes trite scores for movies and modern symphonies to which no one listens. He believes melody is a primitive vulgarity. He is one of Lillian Rearden's friends and a member of the cultural elite.
Clifton Locey is a friend of Jim Taggart who takes the position of vice-president of operation when Dagny Taggart quits.
Pat Logan is the engineer on the first run of the John Galt Line. He later strikes.
Kay Ludlow is a beautiful actress who quit Holywood because of the roles she was given and married secretly the pirate Ragnar Danneskjöld.
Roger Marsh is a producer of electrical equipment who joins the strike. Dagny finds him growing cabbage in Galt's Gulch.
Dick McNamara is a contractor who finished the San Sebastian Line. Dagny Taggart plans to hire him to lay the new Rearden Metal track for the Rio Norte Line, but before she does so, he mysteriously disappears. She later discovers that he has joined the strike and settled in Galt's Gulch.
Cuffy Meigs is the Director of Unification for the railroad business. He carries a pistol and a lucky rabbit's foot, and he dresses in a military uniform, and has been described as "impervious to thought". Meigs seizes control of Project X and accidentally destroys it, demolishing the country's last railroad bridge across the Mississippi River and killing himself, his men, and Dr. Stadler.
Dave Mitchum is a state-hired superintendent of the Colorado Division of Taggart Transcontinental. He is partially responsible for the Taggart Tunnel disaster.
Chick Morrison holds the position of "Morale Conditioner" in the government. He quits when society begins to collapse and flees to a stronghold in Tennessee. His fellow looters consider it unlikely that he will survive.
Horace Bussby Mowen is the president of the Amalgamated Switch and Signal Company, Inc. of Connecticut. He is a businessman who sees nothing wrong with the moral code that is destroying society and would never dream of saying he is in business for any reason other than the good of society. Dagny Taggart hires Mowen to produce switches made of Rearden Metal. He is reluctant to build anything with this unproven technology, and has to be cajoled into accepting the contract. When pressured by public opinion, he discontinues production of the switches, forcing Dagny to find an alternative source.
Midas Mulligan is a wealthy banker who mysteriously disappeared in protest after he was given a court order to lend money to an incompetent applicant. When the order came down, he liquidated his entire business, paid off his depositors, and joined Galt's strike. He is the legal owner of the land where Galt's Gulch is located. Mulligan's birth name was Michael, but he had it legally changed after a news article called him "Midas" in a derogatory fashion, which Mulligan took as a compliment.
Judge Narragansett is an American jurist who ruled in favor of Midas Mulligan during the case brought against him by the incompetent loan applicant. When Narragansett's ruling was reversed on appeal, he retired and joined the strike. At the end of the novel, he is seen editing the United States Constitution, crossing out the contradicting amendments of it and adding an amendment to prohibit Congress from passing laws that restrain freedom of trade.
Ben Nealy is a railroad contractor whom Dagny Taggart hires to replace the track on the Rio Norte Line with Rearden Metal. Nealy is incompetent, but Dagny can find no one better in all the country. Nealy believes that anything can get done with enough muscle power. He sees no role for intelligence in human achievement. He relies on Dagny and Ellis Wyatt to run things, and resents them for doing it, because it appears to him like they are just bossing people around.
Ted Nielsen is the head of Nielsen Motors. He eventually goes on strike, along with most of the other industrialist "producer" types, by closing his motor factory. Dagny later finds him when she visits Galt's Gulch for the first time.
Betty Pope is a wealthy socialite who is having a meaningless sexual affair with James Taggart. She is deliberately crude in a way that casts ridicule on her high social position.
Dr. Potter holds some undefined position with the State Science Institute. He is sent to try to obtain the rights to Rearden Metal.
Dr. Simon Pritchett is the prestigious head of the Department of Philosophy at Patrick Henry University and is considered the leading philosopher of the age. He believes that man is nothing but a collection of chemicals, reason is a superstition, it is futile to seek meaning in life, and the duty of a philosopher is to show that nothing can be understood.
Rearden's mother, whose name is not mentioned, lives with Rearden at his home in Philadelphia. She is involved in charity work, and berates Rearden whenever she can. She dotes on her weak son Philip Rearden.
Philip Rearden is the younger brother of Hank Rearden. He lives in his brother's home in Philadelphia and is completely dependent on him. He is resentful of his brother's charity.
Dwight Sanders owns Sanders Aircraft, a producer of high-quality airplanes, and joins the strike.
Bertram Scudder is an editorial writer for the magazine The Future. He typically bashes business and businessmen, but he never says anything specific in his articles, relying on innuendo, sneers, and denunciation. He wrote a hatchet job on Hank Rearden called The Octopus. He is also vocal in support of the Equalization of Opportunity Bill. Scudder claims that the most important thing in life is "brother love" but seems to have nothing but hatred for those around him. He loses his job after Dagny Taggart reveals her affair with Hank Rearden over air on his radio show.
Claude Slagenhop is president of political organization Friends of Global Progress and one of Lillian Rearden's friends. He believes that ideas are just air, that this is no time for talk, but for action. Global Progress is a sponsor of the Equalization of Opportunity Bill.
Gerald and Ivy Starnes are the two surviving children of Jed Starnes, the founder of the Twentieth Century Motor Company. Together with their since-deceased brother Eric, they instituted a communistic payment-and-benefits program that drove the company into bankruptcy. Gerald, a dying alcoholic, and Ivy, a pseudo-Buddhist ascetic, continue to insist that the plan was perfect and that the failure of their father's company was entirely due to the workers. Eric was a weak, attention-seeking man with a pathological desire to be loved. He committed suicide after the woman he loved married another man. Gerald claims that he always acted for the good of the employees, but he was vain and incompetent and often threw lavish parties using company funds. Ivy, on the other hand, is described as a sadist who relishes seeing others in poverty, but who has no desire for wealth of her own.
Andrew Stockton runs the Stockton Foundry in Stockton, Colorado. When he joins the strike, he opens a foundry in Galt's Gulch. 
Mr. Thompson is the "Head of the State" for the United States. He is not particularly intelligent and has a very undistinguished look. He knows politics, however, and is a master of public relations and back-room deals. Rand's notes indicate that she modeled him on President Harry S. Truman, and that she deliberately decided not to call him "President of the United States" as this title has "honorable connotations" which the character does not deserve.
Lester Tuck is the campaign manager for Kip Chalmers and one of his guests on the train trip to California. He dies in the Taggart Tunnel disaster.
Clem Weatherby is a government representative on the board of directors of Taggart Transcontinental. Dagny considers him the least bad of the government representatives, since he does have some real knowledge on the running of trains. She notices, however, that he is the least appreciated by his own bosses.
The Wet Nurse (Tony) is a young bureaucrat sent by the government to watch over Rearden's mills. Though he starts out as a cynical follower of the looters' code, his experience at the mills transforms him, and he comes to respect and admire the producers. He is shot attempting to inform Hank Rearden about a government plot, but does succeed in warning Rearden just before he dies.
Ellis Wyatt is the head of Wyatt Oil. He has almost single-handedly revived the economy of Colorado by discovering a new process for extracting more oil from what were thought to be exhausted oil wells. When first introduced, he is aggressive towards Dagny, whom he does not yet know and whom he blames for what are, in fact, her brother's policies which directly threaten his business. When the government passes laws and decrees which make it impossible for him to continue, he sets all his oil wells on fire, leaving a single note: "I am leaving it as I found it. Take over. It's yours." One particular burning well that resists all efforts to extinguish it becomes known as "Wyatt's Torch". Later Dagny meets him in Galt's Gulch.