Although his practice was successful, Grisham was not happy and grew restless. He switched to the more lucrative field of civil law and won many cases, but a sense of personal dissatisfaction remained. Hoping to somehow make a difference in the world, he entered politics with the aim of reforming his state\'s educational system. Running as a Democrat, he won a post in the state legislature; four years later, he was reelected. After a total of six years in public office, Grisham, convinced that he would never be able to cut through the red tape of government bureaucracy in his effort to improve Mississippi's educational system, resigned his post in 1990.

While working in the legislature, Grisham continued to run his law office. His first book, A Time to Kill, was inspired by a scene he saw one day in court in which a preadolescent girl testified against her rapist. "I never felt such emotion and human drama in my life," Grisham disclosed to People.

"I became obsessed wondering what it would be like if the girl's father killed that rapist and was put on trial. I had to write it down."

After finishing the manuscript in 1987, Grisham shopped around for an agent to represent him. He was turned down by several before finally receiving a positive response from Jay Garon. Agent and author encountered a similarly difficult time trying to find a publisher; Wynwood Press finally published 5,000 copies of the book and Grisham received a check for $15,000. He purchased 1,000 copies of the book himself, peddling them at garden-club meetings and libraries and giving many of them away to family and friends. Ironically, A Time to Kill is now rated by some commentators as the finest of Grisham's novels. Furthermore, according to Pryor, "Those first editions are now worth $3,900 each," and after being republished, "the novel Grisham . . . couldn't give away has 8.6 million copies in print and has spent 80 weeks on the best-seller lists."

Despite the limited initial success of A Time to Kill, Grisham was not discouraged from trying his hand at another novel. The second time around, he decided to follow guidelines set forth in a Writer's Digest article for plotting a suspense novel. The result was The Firm, the story of a corrupt Memphis-based law firm established by organized crime for purposes of shielding and falsifying earnings.

Grisham was not as motivated when writing The Firm as he had been when composing A Time to Kill, but with his wife's encouragement he finished the book. Before he even began trying to sell the manuscript, he learned that someone had acquired a bootlegged copy of it and was willing to give him $600,000 to turn it into a movie script. Within two weeks, Doubleday, one of the many publishers that had previously rejected A Time to Kill, offered Grisham a contract.

Upon publication, The Firm remained on the New York Times bestseller list for nearly a year, and it sold approximately ten times as many copies as its predecessor. By the time the film version was released, there were more than 7 million copies in print. This amazing success gave Grisham the means he needed to build his dream house, quit his law practice, and devote himself entirely to writing.

In a mere 100 days, Grisham wrote his next legal thriller. The Pelican Brief tells the story of a brilliant, beautiful female law student named Darby Shaw, who postulates a theory about the murder of two Supreme Court justices are murdered and consequently endangers her life. Despite criticism that The Pelican Brief was largely modeled on The Firm in style as well as premise, Grisham was also praised for creating another exciting page-turner. Made into a film starring Denzel Washington and Julia Roberts, The Pelican Brief sold millions of copies.

His next mystery novel, The Client, was likewise a bestseller and became a major motion picture. This legal thriller focuses on a young boy who, after learning a sinister secret, turns to a motherly lawyer for protection from both the mob and the FBI. Like his earlier works, the book drew lukewarm reviews, but Grisham was nonetheless in the rare and enviable position of having a book at the top of the hardcover bestseller list and books in the first, second, and third spots on the paperback bestseller list.

With his fifth novel, Grisham departed from his proven formula and proceeded at a more leisurely pace. He took a full nine months to write The Chamber, a book in which the "good guys" and "bad guys" are not as clearly defined as in his previous efforts. The novel tells the tale of Ku Klux Klansman Sam Cayhall, who is on death row for the murder of two young sons of a Jewish civil rights attorney. After languishing in prison for years, Cayhall is surprised by the arrival of his estranged grandson, Adam Hall. Hall, an attorney, sets out to reverse his grandfather's death sentence, even though he considers Sam to be the family demon. While this book was less obviously commercial than his previous three books, Grisham had little trouble selling the movie rights to The Chamber for a record fee. The movie, starring Chris O'Donnell and Gene Hackman, was released in 1996.

Grisham's 1995 novel, The Rainmaker, features a young lawyer, Rudy Baylor, recently graduated from law school, who finds himself desperate for a job when the small firm he had planned to work for is bought out by a large, prestigious Memphis firm that has no use for him. After going to work for Bruiser Stone, a shady lawyer with underworld clients, Baylor finds himself averting an FBI raid on Stone's firm while also trying to pursue a lawsuit brought by a terminally ill leukemia patient against an insurance company that has refused to pay for her treatment. The book was made into a successful motion picture starring Matt Damon and Claire Danes and released in 1997.

Grisham garnered surprisingly warm critical comments for his next novel, 1996's The Runaway Jury. Set in a Mississippi gulf coast town, the novel features a legal showdown between several large tobacco companies… "Big Tobacco," in Grisham's parlance… and the widow of a man who died of lung cancer after smoking heavily for three decades. At issue in the trial are the makeup and actions of the jury. Big Tobacco hires the ruthless Rankin Fitch to influence the jury in subtle ways to ensure that it will acquit the tobacco companies of any wrongdoing, but Fitch finds himself challenged unexpectedly by a mysterious man, Nicholas Easter, who gets himself appointed to the jury. Along with his girlfriend, Marlee, Easter appears to have even greater influence over the actions of the jury than Fitch does.

Grisham continued his streak of phenomenally popular novels with 1997's The Partner, about a law-firm partner who fakes his own death and absconds with $90 million. In pursuit are his former partners and a shady defense contractor who had planned to split the millions, which were generated by a fraudulent claim. With the help of a mysterious Brazilian, Eva Miranda, the fugitive figures out an ingenious scheme to hide the money but is unable to avoid the pursuit of his enemies.

In the span of a few short years, Grisham has realized greater success than most writers will enjoy in a lifetime. But the former lawyer and politician remains realistic about his limitations and feels that a time may come when he will walk away from writing just as he previously abandoned both law and politics. In his interview with Bearden, he compared writers to athletes: "There’'s nothing sadder than a sports figure who continues to play past his prime."