Fitzgerald returned to his parents' house at 599 Summit Avenue, on Cathedral Hill, in St. Paul to revise The Romantic Egoist. Recast as This Side of Paradise, about the post-WWI flapper generation, it was accepted by Scribner's in the fall of 1919, and Zelda and Scott resumed their engagement. The novel was published on March 26, 1920, and became one of the most popular books of the year. Scott and Zelda were married in New York's St. Patrick's Cathedral. Their daughter and only child, Frances Scott "Scottie" Fitzgerald, was born on October 26, 1921.
 "The Jazz Age"
The 1920s proved the most influential decade of Fitzgerald's development.The Great Gatsby, considered Scott's masterpiece, was published in 1925. Fitzgerald made several excursions to Europe, notably Paris and the French Riviera, and became friends with many members of the American expatriate community in Paris, notably Ernest Hemingway.
Hemingway looked up to Fitzgerald as an experienced professional writer. Hemingway greatly admired The Great Gatsby and wrote in his A Moveable Feast "If he could write a book as fine as The Great Gatsby I was sure that he could write an even better one" (153). Hemingway expressed his deep admiration for Fitzgerald, and Fitzgerald's flawed, self-defeating character, when he prefaced his chapters concerning Fitzgerald in A Moveable Feast with:
- His talent was as natural as the pattern that was made by the dust on a butterfly's wings. At one time he understood it no more than the butterfly did and he did not know when it was brushed or marred. Later he became conscious of his damaged wings and their construction and he learned to think and could not fly any more because the love of flight was gone and he could only remember when it had been effortless. (129)
Much of what Hemingway wrote in A Moveable Feast helped to establish the myth of Fitzgerald's dissipation and loss (of ability, social control, and life) and Zelda's hand in that demise. Though the bulk of Hemingway's text is factually correct, it is also colored by his disappointment in Fitzgerald, as well as Hemingway's own rivalrous response towards any competitor, living or dead. That disappointment was most evident in The Green Hills of Africa, where he specifically mentions Fitzgerald as an archetypal ruined American writer; Hemingway had been both shocked and unnerved by Fitzgerald's account of his own difficulties in his nonfiction essays and notebooks from the 1930s, published as The Crack-Up (with Edmund Wilson as editor) in 1945.
Fitzgerald’s friendship with Hemingway was tumultuous, as many of Fitzgerald’s relationships would prove to be. (As, indeed, were many of the thrice-divorced Hemingway's.) Hemingway did not get on well with Zelda, either. He claimed that she “encouraged her husband to drink so as to distract Scott from his ‘real’ work on his novel,"1 the other work being the short stories he sold to magazines. This “whoring”, as Fitzgerald, and subsequently Hemingway, called these sales, was a sore point in the authors’ friendship. Fitzgerald claimed that he would first write his stories in an authentic manner but then put in “twists that made them into saleable magazine stories.”²
But the marriage was mixed—both destructive and constructive. Fitzgerald drew largely upon his wife's intense and flamboyant personality in his writings, at times quoting direct passages from her letters and personal diaries in his work. Zelda made mention of this in a 1922 mock review in the New York Tribune, saying that "[i]t seems to me that on one page I recognized a portion of an old diary of mine which mysteriously disappeared shortly after my marriage, and also scraps of letters which, though considerably edited, sound to me vaguely familiar. In fact, Mr. Fitzgerald—I believe that is how he spells his name—seems to believe that plagiarism begins at home" (Zelda Fitzgerald: The Collected Writings, 388). But the impact of Zelda's personality on his work and life is often overstated, as much of his earliest writings reflect the personality of a first love, Ginevra King. In fact, the character of Daisy as much represents his inability to cultivate his relationship with King as it does the ever-present fact of Zelda. (Although Gatsby's economic failure to immediately wed Daisy in 1917, with an eventual return in financial triumph, does closely mirror Fitzgerald's own experiences with his future wife.)
Although Fitzgerald's passion lay in writing novels, only his first novel sold well enough to support the opulent lifestyle that he and Zelda adopted as New York celebrities. As did most professional authors at the time, Fitzgerald supplemented his income by writing short stories for such magazines as The Saturday Evening Post, Collier's Weekly, and Esquire, and sold movie rights of his stories and novels to Hollywood studios. Many of these stories act as testing grounds for his novels. For example, "Absolution" was intended as an earlier chapter in The Great Gatsby. Because of this lifestyle, as well as the bills from Zelda's medical care when they came, Fitzgerald was constantly in financial trouble and often required loans from his literary agent, Harold Ober, and his editor at Scribner's, Maxwell Perkins. When Ober decided not to continue advancing Fitzgerald, the author severed ties with his longtime friend and agent. (Fitzgerald offered a good-hearted and apologetic tribute to this support in the late short story "Financing Finnegan.")
Fitzgerald began working on his fourth novel during the late 1920s but was sidetracked by financial difficulties that necessitated his writing commercial short stories, and by the schizophrenia that struck Zelda in 1930. Her emotional health remained fragile for the rest of her life. In 1932, she was hospitalized in Baltimore, Maryland. Scott rented the "La Paix" estate in the suburb of Towson, Maryland to work on his latest book, the story of the rise and fall of Dick Diver, a promising young psychiatrist who falls in love with and marries Nicole Warren, one of his patients. The book went through many versions, the first of which was to be a story of matricide. Some critics have seen the book as a thinly-veiled autobiographical novel recounting Fitzgerald's problems with his wife, the corrosive effects of wealth and a decadent lifestyle, his own egoism and self-confidence, and his continuing alcoholism. Indeed, Fitzgerald was extremely protective of his material (their life together). When Zelda wrote and sent to Scribner's her own fictional version of their lives in Europe, Save Me the Waltz, Fitzgerald was angry and was able to make some changes prior to the novel's publication, and convince her doctors to keep her from writing any more about what he called his "material," which included their relationship. His book was finally published in 1934 as Tender Is the Night. Critics who had waited nine years for the followup to The Great Gatsby had mixed opinions about the novel. Most were thrown off by its five-part structure and many felt that Fitzgerald had not lived up to their expectations. The novel did not sell well upon publication, but like the earlier Gatsby, the book's reputation has since risen significantly.
 Hollywood years
Although he reportedly found movie work degrading, Fitzgerald was once again in dire financial straits, and, like Hemingway, spent the second half of the 1930s in Hollywood, working on commercial short stories, scripts for Metro-Goldwyn-Mayer (including some unfilmed work on Gone with the Wind), and his fifth and final novel, The Love of the Last Tycoon. Published posthumously as The Last Tycoon, it was based on the life of film executive Irving Thalberg. Scott and Zelda became estranged; she continued living in mental institutions on the east coast, while he lived with his lover Sheilah Graham, a gossip columnist, in Hollywood. From 1939 until his death, Fitzgerald mocked himself as a Hollywood hack through the character of Pat Hobby in a sequence of 17 short stories, later collected as "The Pat Hobby Stories"
 Illness and death
Fitzgerald had been an alcoholic since his college days, and became notorious during the 1920s for his extraordinarily heavy drinking, leaving him in poor health by the late 1930s. According to Zelda's biographer, Nancy Milford, Scott claimed that he had contracted tuberculosis, but Milford dismisses it as a pretext to cover his drinking problems. However, Fitzgerald scholar Matthew J. Bruccoli contends that Fitzgerald did in fact have recurring tuberculosis, and Nancy Milford reports that Fitzgerald biographer Arthur Mizener said that Scott suffered a mild attack of tuberculosis in 1919, and in 1929 he had "what proved to be a tubercular hemorrhage". Some have said that hemorrhage was caused by bleeding from esophageal varices.
Fitzgerald suffered two heart attacks in late 1940. After the first, in Schwab's Drug Store, he was ordered by his doctor to avoid strenuous exertion and to obtain a first floor apartment. He moved in with Sheilah Graham, who lived on the first floor. On the night of December 20, 1940, he had his second heart attack, and the next day, December 21, while awaiting a visit from his doctor, Fitzgerald collapsed in Graham's apartment and died.
Among the attendants at a visitation held at a funeral home in Hollywood was Dorothy Parker, who reportedly cried and murmured "the poor son of a bitch", a line from Jay Gatsby's funeral in Fitzgerald's The Great Gatsby. In a strange coincidence, the author Nathanael West, who was a friend and admirer of Fitzgerald, was killed along with his wife Eileen McKenney in El Centro, California, while driving back to Los Angeles to attend Fitzgerald's funeral service.
Fitzgerald's remains were then shipped to Maryland, where his funeral was attended by very few people. The church would not allow him to be buried in his family's plot in Rockville and he was originally buried in Rockville Union Cemetery. Zelda died tragically in a fire at the Highland Mental Hospital in Asheville, North Carolina, in 1948. With the permission and assistance of their only child, Frances "Scottie" Fitzgerald Lanahan Smith, the Women's Club of Rockville had their bodies moved to the family plot in Saint Mary's Cemetery, in Rockville, Maryland.
Fitzgerald never completed The Love of the Last Tycoon. His notes for the novel were edited by his friend Edmund Wilson and published in 1941 as The Last Tycoon. In 1994, the book was rereleased under the original title The Love of the Last Tycoon, which is now agreed upon as Fitzgerald's intended title.