Born Donald Patrick Conroy, he was the eldest of seven children (five boys and two girls) born to Marine Colonel Donald Conroy, of Chicago and the former Frances "Peggy" Peck of Georgia.

Conroy's stories have been heavily influenced by his upbringing. His father, a US Marine Corps pilot, was physically and emotionally abusive toward his children, and the pain of a youth growing up in such a harsh environment is evident in Conroy's novels, particularly The Great Santini. Military assignments also caused the family to move frequently, and Conroy claims to have moved 23 times before he was 18.

While he was living in Orlando, Florida, Conroy's 5th grade basketball team defeated a team of 6th graders, making the sport his prime outlet for bottled-up emotions for more than a dozen years.

Conroy is a graduate of The Citadel, and his experiences there provided the basis for two of his best-known works, the novel The Lords of Discipline and the memoir My Losing Season. The latter details his senior year on the school's underdog basketball team, which won the longest game in the history of Southern Conference basketball against rival Virginia Military Institute in quadruple overtime in 1967.

His first book, The Boo, is a collection of anecdotes about cadet life centering on Lt. Colonel Nugent Courvoisie, who had served as Assistant Commandant of Cadets at the Citadel from 1961 to 1968 (Courvoisie appears as the fictional character Colonel Thomas Berrineau, a.k.a. "The Bear," in The Lords Of Discipline). After completing The Boo, Conroy couldn't find a publisher for the book, so he self-published it.

After graduating from the Citadel, Conroy taught English in Beaufort, South Carolina. While there he met and married Barbara Jones, a young widow of the Vietnam War who had two children (whom he adopted). He then accepted a job teaching children in a one-room schoolhouse on remote Daufuskie Island, South Carolina.

Conroy was fired at the conclusion of his first year on the island for his unconventional teaching practices, including his refusal to use corporal punishment on students, and for his lack of respect for the school's administration. Conroy wrote his book The Water Is Wide based on his experiences as a teacher. The book won Conroy a humanitarian award from the National Education Association and was made into a feature film, Conrack, starring Jon Voight in 1974. Hallmark produced a television version of the book in 2006.

In 1976, Conroy published his first novel, The Great Santini. The main character of the novel is Marine fighter pilot Colonel "Bull" Meecham, who dominates and terrorizes his family. Bull Meecham also psychologically abuses his teenage son Ben. The character is based on Conroy's father Donald. (According to My Losing Season, Donald Conroy was even worse than the character depicted in Santini.)

The Great Santini earned Pat Conroy a lot of trouble with his family, who felt that he had betrayed family secrets by writing about his father. Members of his mother's family would picket Conroy's book signings, passing out pamphlets asking people not to buy the novel. The friction contributed to the failure of his first marriage. However, the book also eventually helped repair Conroy's relationship with his father, and they became very close. His father, looking to prove that he was not like the character in the book, changed his manners drastically. According to Conroy, his father would often sign copies of his son's novels as "Donald Conroy - The Great Santini. I hope you enjoy my son's work of fiction!" The novel was made into a film of the same name in 1979, starring Robert Duvall.

Publication of The Lords of Discipline in 1980 upset many of his fellow graduates of The Citadel, who felt that his portrayal of campus life was highly unflattering. The rift was not healed until 2000, when Conroy was awarded an honorary degree and asked to deliver the commencement address the following year. As Pat Conroy says in the novel, "I wear the ring", meaning that as a graduate of the Citadel, he has a right to comment on it.

In 1986, Conroy published what is arguably his most acclaimed and well-known novel - The Prince of Tides. The book tells the story of Tom Wingo, an unemployed South Carolina teacher who goes to New York City to help his sister, Savannah, a poet who has attempted suicide, to come to terms with their past. The book is partly based on Conroy's relationship with his sister, Carol. After the book was published, Conroy's sister stopped speaking to him for several years. Again, the novel was made into a film of the same name in 1991, starring Nick Nolte and Barbra Streisand.

In 1995, Conroy published Beach Music, a novel about an American ex-patriate living in Rome who returns to South Carolina upon news of his mother's terminal illness. The story reveals his attempt to confront personal demons, including the suicide of his wife, the subsequent custody battle with his in-laws over their daughter, and the attempt by a film-making friend to rekindle old friendships which were compromised during the days of the Vietnam War.

In 2009, Conroy published South of Broad, which again uses the familiar backdrop of Charleston following the suicide of newspaperman Leo King's brother, and alternates narratives of a diverse group of friends between 1969 and 1989. His recent non-fiction work, The Pat Conroy Cookbook, is a collection of favorite recipes accompanied by stories about his life, including many stories of growing up in South Carolina.

Conroy's South Carolina roots clearly show in all his work. Indeed, a critic compiling a list of the leading current practitioners of Southern narrative writing listed him in the same sentence as Fannie Flagg and John Kennedy Toole and in the same paragraph as Walker Percy and Eudora Welty.

Conroy has been married three times.

His first marriage was to Barbara (née Bolling) Jones on 10 October 1969, while he was teaching on Daufuskie Island. Jones, who had been Conroy's next door neighbor in Beaufort, South Carolina, had been widowed when her first husband, Joseph Wester Jones III, a fighter pilot stationed in Vietnam, had been shot down and killed. Jones already had one daughter, Jessica, and was pregnant at the time of her husband's death with their second child, Melissa. Conroy adopted both girls after he married their mother, and then they had a daughter of their own, Megan. They divorced in 1977.

Conroy then married Lenore (née Gurewitz) Fleischer in 1981. He became the stepfather to her two children, Gregory and Emily, and the couple also had one daughter, Susannah. They divorced on 26 October 1995.

Conroy married his third wife in May 1997, writer Cassandra King, who is the author of four popular novels.

He currently lives on Fripp Island, South Carolina, with wife Cassandra. Conroy has commented that his wife is a much happier writer than he is. In an interview with the Atlanta Journal-Constitution, he commented: "I'll hear her cackle with laughter at some funny line she's written. I've never cackled with laughter at a single line I've ever written. None of it has given me pleasure. She writes with pleasure and joy, and I sit there in gloom and darkness."

Conroy's friend, political cartoonist Doug Marlette, died in a car accident in July 2007. Conroy and Joe Klein eulogized Marlette at the funeral. There were 10 eulogists in all, and Conroy called Marlette his best friend, and said: "The first person to cry, when he heard about Doug's death, was God."

Conroy was inducted into the South Carolina Hall of Fame on 18 March 2009.