His longtime spokesman Trav Robertson said the retired Air Force general and treasurer of 37 years died of natural causes.
Patterson was from the textile town of Calhoun Falls. He flew combat missions for the Army at Iwo Jima, and, in the Air Force, during the Korean War and the Berlin crisis.
His interest in flight was sparked one day while working on his family's Abbeville County farm.
"One day, I was out in the field chopping cotton and these three yellow and gold planes flew over," he said in January 2007. "I looked up and said, 'Hmmm. I believe I'd like to do that.'"
He was called up as an Army Reserve member while attending Clemson University and got his first chance at the controls.
"You just kind of think fast. 'Here I am in this thing by myself,'" he said of his first solo flight. Flying taught him always to "anticipate what's coming next," he said.
After the war, Patterson earned a law degree from the University of South Carolina and joined the South Carolina Air Force National Guard.
The Berlin crisis was a Cold War confrontation that eventually led East Germany to erect the Wall in 1961 to stop the flow of refugees out of the Soviet occupation zone to the West. Robertson said Patterson's unit flew to Berlin from Spain to protect planes and supplies going to and from the city in case the Russians attacked.
Upon his retirement from the Air National Guard in 1984, the Legislature promoted Patterson to lieutenant general. He had flown every combat plane stationed in South Carolina, from the P-51 through the F-16. President Reagan awarded him the Distinguished Service Medal of the United States.
"He was a dedicated family man, public servant and an American hero," reads a release sent by Robertson. "Instead of using his energy and talents for other endeavors, he gave his life to the people of South Carolina."
Patterson served as an assistant attorney general for eight years before first winning the treasurer's office in 1966, following the death of longtime state Treasurer Jefferson Bates. Years later, he recalled spending less than $10,000 on that first campaign.
"Things were cheaper then, particularly politics," he said in 2007.
For nine terms, he held the job of paying the state's bills and making money through investments. As treasurer, he sat on the state's five-member Budget and Control Board that handles billions in spending and borrowing decisions.
"I could always depend on his wise counsel and his willingness to put aside partisan politics to do what was best for the people of South Carolina," said former Republican Gov. David Beasley.
Patterson lost a 1994 re-election bid to now-Comptroller General Richard Eckstrom but defeated him in 1998 to win the seat back.
Patterson was the lone Democratic incumbent in statewide office seeking re-election in 2006, making him a GOP target. He lost to Republican Thomas Ravenel, who resigned in July 2007 amid a federal cocaine charge. Ravenel pleaded guilty to possession two months later.
As Patterson packed 30 boxes of memories, books and plaques in January 2007, photos left in his office included a picture of him crouched in front of an F-16 at the end of his military service as a major general in the South Carolina National Guard, and of a P-51 Mustang like the one he flew around Iwo Jima.
As he left his job of nearly four decades, Patterson said he "enjoyed every minute of it," and said the main lesson he learned about keeping the state's finances was to "live within your means."
"You have to live within the revenues that your tax base generates," he said.
Gov. Mark Sanford, who worked to help defeat Patterson in 2006, noted his death came on the 68th anniversary of the Japanese attack on Pearl Harbor.
"It strikes me as significant that his passing comes on the same day we remember the sacrifice and service of so many of his fellow servicemen in World War II at Pearl Harbor," Sanford said in a statement.
Current Treasurer Converse Chellis noted Patterson was called "Mr. P" by office staff.
"He was a part of our country's 'Greatest Generation' and our nation is better because of Mr. Patterson's service," Chellis said in a release. He "worked diligently to safeguard South Carolina's finances and make our state a better place. He succeeded."
Patterson is survived by his wife Marjorie, six children and 13 grandchildren.
Visitation will be 7-9 p.m. Wednesday at Shandon Presbyterian Church, where he served as a deacon and an elder. The funeral will be 1 p.m. Thursday at the church. Burial will follow at Elmwood Cemetery with full military honors.
GRADY LESLIE PATTERSON JR.
BORN: Jan. 13, 1924 in Calhoun Falls
EDUCATION: Bachelor's and law degrees from the University of South Carolina.
CAREER: The World War II fighter pilot flew combat missions from Iwo Jima then flew during the Korean War as an Air Force pilot.
POLITICAL EXPERIENCE: Served as treasurer from 1966 to 1995, when he lost to Republican Richard Eckstrom. Patterson defeated Eckstrom in the 1998 race. He defeated Greg Ryberg in 2002 to keep the job but lost to Republican Thomas Ravenel in 2006.
PERSONAL: He is survived by his wife, Marjorie, six children, and 13 grandchildren.