Visionary student architect Howard Roark strives to break away from the classically inspired designs of ordinary architects.  His unwillingness to compromise, despite the advice of his ambitious friend, Peter Keating, causes him to be kicked out of school, but earns him a job with Henry Cameron, a talented architect, who also believes that form must follow function.

After Cameron is completely destroyed by the system, Roark sets up his own company, but gets only an occasional job.  Roark is offered a commission to build a bank building, but when he learns that the bank wants him to add some classical touches, he rejects the commission, to the secret delight of Ellsworth Toohey, the architectural critic at the Bulletin newspaper.  Gail Wynand, the owner of the Bulletin, holds a controlling interest in the bank, and when he asks Toohey to suggest a replacement for Roark, Toohey suggests the now successful Peter Keating.  Wynand is not impressed with Peter's work and consults with Dominique Francon, the paper's other architectural writer, whose father is Peter's partner.  Even though Peter is Dominique's fiancée, she refuses to recommend him and her ferocious independence so impresses Wynand that he falls in love with her.

Later, at a dinner party, Wynand offers the commission to Peter if he will break his engagement to Dominique.  After Peter accepts the commission and leaves Wynand's apartment, Wynand proposes to Dominique, but, saying that she is incapable of feeling, Dominique turns him down.  She then leaves New York for her father's country house.  There she meets Roark, who has taken a job working at a nearby quarry.  Although they never exchange names, they are instantly drawn to each other.  After a brutal sexual encounter with Dominique, Roark returns to the city, where a man named Enright offers him work.

At Toohey's suggestion, the Bulletin starts a campaign against the Enright Building.  Dominique, impressed by the design, begs Wynand to call off the campaign, and when he refuses, she resigns.  The building completed, Enright throws a party in Roark's honor, and for the first time, Dominique learns the identity of her mysterious lover.  Later, she visits Roark in his apartment and tells him that even though she loves him, she will never see him again as she cannot bear to see him destroyed.  Roark admits that he returns her love and adds that he will wait for her until she has learned not to be afraid of the world.  Immediately after leaving Roark, Dominique asks Wynand to marry her.

Slowly, Roark gets commissions for small buildings, farms, gas stations and homes from people who have seen his work and like it.  Eventually Wynand asks Roark to build a country home for him and Dominique.  When Dominique learns who is designing the house, she reminds Wynand of the Bulletin's campaign against Roark, but Wynand is charmed by the architect, and he becomes a frequent guest of the couple.  Meanwhile, Peter has started to lose business.  He begs Roark to help him design the Cortlandt Homes, a housing project, and Roark, realizing that he would never be able to get his own design past Toohey, agrees on condition that Peter promise it will be built exactly as he specifies.

Peter does not have the strength of character to enforce Roark's wishes, and Roark returns from a vacation to witness the construction of a greatly altered building.  With Dominique's help, he blows up the project and then admits his guilt.  Wynand's is the only paper to stand behind Roark, and Toohey and his cronies are able to whip up public opinion against both Roark and Wynand.

In order to save his paper, Wynand is forced to condemn his friend.  Despite all of Toohey's efforts, however, Roark's impassioned speech in favor of individualism causes the jury to acquit him.  Enright then buys the Cortlandt project and gives it to Roark to build as he chooses.  Wynand offers Roark a contract to design the Wynand Building and, after the contract is signed, kills himself.  Roark designs the Wynand Building to be the tallest in the city and finally marries Dominique.

Notes
The film is based on the novel The Fountainhead by Ayn Rand (New York, 1943).  Like Ayn Rand's novel, the film, which she also wrote, depicts her concern with the rights of the individual over the demands of society and expounds her belief that genius entitles the superior man to ignore moral and ethical constraints.  The character of "Howard Roark" was ostensibly based on architect Frank Lloyd Wright.

A September 18, 1945 HR news item noted that Warner Bros. wanted to borrow Alan Ladd from Paramount to co-star in the film with Lauren Bacall, while a January 24, 1945 HR news item reported that Mervyn LeRoy was to direct the film with stars Humphrey Bogart and Barbara Stanwyck.  According to a February 19, 1948 NYT article, Harriet Frank, Jr. was hired to adapt Rand's novel for the screen, but only Rand received screenplay credit.  Among the actresses considered for the lead were Bette Davis and Greta Garbo, according to a June 21, 1948 HR news item.  A modern source reports that Barbara Stanwyck had urged Warner Bros. to purchase Rand's novel in 1943.  MGM star Clark Gable, who had wanted to play the role of "Howard Roark," later told Rand that he had complained to the studio for not protecting his interests by buying the novel for him.  The quarry scenes were shot on location near Fresno, California, according to a July 13, 1948 HR news item.

Modern sources add the following information about the film: Ayn Rand agreed to write the script providing that nothing would be changed without her permission.  Director King Vidor wanted Frank Lloyd Wright to design the film, but his fee of $250,000 was not approved by Jack L. Warner.  Edward Carrere's sets were scorned by the architectural press.  Interiors critic George Nelson, as quoted in a modern source reprint, called the sets the "silliest travesty of modern architecture that has yet hit the film," and "a total perversion of formal and structural elements."