In November 1861 he enlisted in the Union Army during the U. S. Civil War.  Although the state of Kentucky was split in its allegiances between North and South, Stagg’s religious views on slavery likely motivated his choice to join the Union.  Early in his tenure as a soldier George gained a reputation for his bare knuckle fighting in the ring. His unit was the 21st Kentucky Infantry Regiment and they saw significant combat, taking part in the Battle of Franklin, Battle of Nashville, Battles of Stone River, Battle of Kennesaw Mountain, and in the siege of Atlanta.  Throughout the war, the 21st Kentucky lost 67 enlisted men and three officers killed, with another 178 dying of disease.

Throughout the war, Stagg remained steady proving his tenacity which allowed him to rise through the ranks as his courage and ability were recognized.  He received a field commission to first lieutenant in January 1862 and a promotion to Captain a year later.  By the summer of 1863 he was chosen as an Aide-d-Camp to General Ambrose Burnside. 

When the Civil War ended, George moved with his growing family to St. Louis,  Missouri, where he met a wealthy local businessman named James Gregory.  Gregory was impressed with the 31 year-old Stagg. Perhaps due to the regimented military lifestyle he had led for the last four years George developed an extremely high sense of organization, meticulousness in keeping records, and leadership qualities.  With his new partner they established a new company called “Gregory & Stagg, Commercial Merchants & Distillers’ Agents.”  It meant that Stagg was busy selling Kentucky whiskey in markets throughout the mid west and regionally around the United States.

His work brought him in contact with distillers and whiskey rectifiers of St. Louis and other Midwest cities. In 1873 a severe financial downturn through out the world threw many previously successful distillers into serious financial trouble.  Among them was Colonel Edmund Haines Taylor, Jr. considered the king of Kentucky bourbon. The Louisville Courier-Journal reported in June 1877 that Taylor owed Gregory & Stagg’s firm $150,000 (the equivalent to four million dollars today). 

Stagg saw Taylor’s financial plight as an opportunity.  Up to this time he had been considered a gifted salesman, a pitchman for Kentucky whiskey but not a real player in the industry.  Stagg set out to change all that and the two partners paid off Taylor’s loans and as a result gained control of the Colonel’s two distilleries, located adjacent to each other on the Kentucky River at Leestown on the Frankfort Turnpike. One was known as the O.F.C. (Old Fire & Copper) Distillery and the other the Carlisle Distillery, named for John G. Carlisle, then a congressman from Kentucky, later Secretary of the Treasury. 

Stagg recognized that keeping Taylor and especially his name associated with the enterprises was important. He established the E. H. Taylor Jr. Company in 1879, with himself as president and Taylor as vice president.   Stagg had 3,448 of 5,000 shares in the company; he gave Taylor, who was overseeing one of the distillery operations, the balance of the shares.

During the six years Taylor was working for Stagg, relations between them deteriorated sharply. By late 1886 the Colonel was straining to exit the company.  Clearly tired of dealing with the George’s stubborn personality,  So Stagg cut him a deal, in return for Taylor’s share of the stock, he the Colonel back a third distillery he had acquired. Later that distillery became known as the “Old Taylor Distillery.”

Although he agreed to take Taylor’s name off everything related to his holdings Stagg believed later that the Colonel’s reputation for quality whiskey had spread beyond Kentucky to the entire Nation and throughout the world. Having his name on the corporate letterhead was significant. Taylor was outraged by Stagg’s change of mind and began a series of contentious and costly lawsuits against him.  When the last of these court actions were settled in 1890, the company adopted the name George C. Stagg and Co.  Now the liquor salesman turned distiller had his name in the forefront of the Kentucky whiskey industry. 

With Taylor’s departure, Stagg’s work load had increased dramatically. In addition running two distilleries that were in over-production mode, his company had drooping sales, whiskey prices were going down and government authorities were a constant annoyance. Moreover, his health was failing and by the early 1890’s George had retired.  Not long after that, he died in 1893 at the young age of only 58.

Industry experts and fans of bourbon at the time knew that Stagg's Distillery was “a plus one in class and ultra taste,” in fact it was called "the best of  the best." Stagg’s salesmanship and stewardship of the business made the Distillery into the world’s leading bourbon producer. In 1904, the Distillery name was changed in his name, "The George T. Stagg Distillery" which is a title that was lasted for over a century. In the year 2000 Whisky Advocate Magazine named the factory "Distillery of the Year" and it was still going by the name Stagg.