George Reeg, Jr. was born in Allegheny County, Pennsylvania, to German immigrant George Adam Reeg and his Pennsylvania born wife Helena B. Hoffman. He was the oldest of seven siblings, including Elmer William (9/15/1889), Arthur Baltzher (11/13/1893), Theodore Henry (4/1/1896), Helen M. (2/1898), Otto Jacob (12/28/1899), and Elsie (1903). The elder George was originally a blacksmith. He and his brother Adam then worked as butchers in Pittsburgh, and are listed in city directories in that capacity from the early to mid-1890s. By 1897, George had invested in a saloon at 532 3rd Street in Allegheny (now part of Pittsburgh). The 1900 census showed George and his family living in the same complex as Adam Reeg and Helena's family, the Hoffmans, with George working as a bartender, and his older brother Baltzher also residing in the crowded household. George, Jr., still just 12, was listed as an errand boy, likely working for his father and/or uncle.

It is unclear how much musical training the younger George had, but it appears to have gone beyond what was usually offered in the public schools. He may have played in his father's saloon, and was likely exposed to some ragtime in his teens as many itinerant musicians made their way through Pittsburgh during that era. In 1903 George, Sr., parlayed his holdings into a hotel with a saloon, with Helena running much of the lodging operation and George the saloon, while their offspring assisted wherever they could in the enterprise. However, the younger George, although he continued to live with parents after graduating high school, had his eye on a career as a musician. He got a job in his late teens with the Volkwein Brothers Music Store and Publishing Company in Pittsburgh, run by Jacob C. and Rudolph G. Volkwein, and would work on and off for them for more than a decade. Reeg's first published composition appeared in 1907 when he was still 19, a Maudlin ballad written with his friend William Covert. They followed it up with another song in 1908, a tepid Dixie tune. The 1908 and 1909 Pittsburgh city directories had George listed as a musician. It was also a more successful year for the young composer, who had three releases, including Dixie Jingles issued in New York City by dominant publisher Jerome H. Remick.

While the younger George was not found in the 1910 census, he was temporarily residing in Chicago, Illinois, possibly working as a pianist, according to a newspaper mention and a directory listing. Although there is some possibility he was representing the Volkweins in that city, there is no strong evidence to support this contention. It was in Chicago that George met Czech immigrant Marie C. Dvorak, whom he married on June 14, 1911. By the end of the year, he and his new wife were back in Pittsburgh and residing with the rest of the family at the hotel, at least temporarily. In 1912, George's best known work was issued in Boston by Walter Jacobs, who had also acquired his 1909 composition Ram Rod Rag. The new one, Piccalilli Rag, was better than average, featuring a full eight bar introduction, and some interesting variations on the call and response figures found in many folk-based rags. The title most likely was referring to British vegetable concoction based on cauliflower (originally pickle), mustard and tumeric, possibly with roots in India. The rag was a relatively good seller for Jacobs, and found its way to a couple of piano rolls as well. Other output that year included another song written with Covert, a fine waltz, and two variations on one theme, The Last Hope, issued as a meditation and waltz. Another issue on November 29, 1912, was that of Mary Reeg (some sources show Marie like her mother), born in Pittsburgh.

While some of Reeg's works of the next few years were issued by publishers from Boston and New York to Cleveland and Cincinnati, Ohio, many more were issued by his employers, the Volkweins. For the next few years, George would be variously listed in Pittsburgh city directories as a clerk or salesman working for their firm, most likely in the store selling pianos and other musical instruments. Among the more interesting issues of 1913 from this collaboration came Bits of Old-Time Hits, which was actually a set of band and orchestral arrangements of what were then considered to be old chestnuts, but in a fresh new setting. In 1914, just as war was breaking out in Europe and some mild concerns were voiced about it in the United States, he came out with The Emblem of Peace published by the Volkweins. "Respectfully dedicated to our President Woodrow Wilson," it was issued too early to take advantage of the wave of patriotism and anti-war sentiment that would soon be prevalant in America. The Volkweins reissued at the end of the war, but it was too late for George. His second child, George A. Reeg III, was born on September 22, 1914, in the Reeg's new home of West View, Pennsylvania, just northwest of downtown Pittsburgh.

In 1915 George released yet another syncopation, his Jubilee Rag, which saw a successful arrangement by J.S. Zamecnik as issued by Sam Fox in Cleveland. Most of the rest of his output was what may be considered to be light classics or parlor music, including some waltzes, reveries and typical ballads. One of those was touted, likely by the publisher, in the October 28, 1916, edition of the Music Trade Review:

On his June 5, 1917 draft record, George listed as a probable cause for his not being able to serve in the military as his being the sole support for his wife and children, and his "old feeble mother." Helena had been widowed for nearly three years at that point, but at 55 years old, it was unlikely she was all that feeble, a point that time and future events would tragically prove. In fact, she had taken over the daily operation of the family hotel. Some six months later George landed in the hospital with a serious ailment, and before the month of January was out, died of an illness that is hard to discern from his death certificate, show what appears to be "dedrun glotta." The cause appears to have been a virus that weakened him, but predated the deadly flu virus that would spread at the end of the year. The Music Trade Review of February 9th, 1918 noted the event:

This was just the beginning of the heartbreak that Helena would experience in the short run, as well as Marie Reeg. On May 13, 1919, Theodore Reeg was shot in the saloon that he was now running in his mother's hotel and died in what was classified as a murder. The following month, on June 13, George's 6-year-old daughter Marie died in Cicero, Illinois, where the elder Marie had moved to reside with her children and parents. She was followed on March 23, 1923, by her brother, George II, who passed away at age 8 in Chicago. Arthur Reeg succumbed to tuberculosis in Pittsburgh on May 6, 1926. Otto Reeg died on July 19, 1928, of cardiac failure after having undergone a tonsillectomy. The one known survivor of this Reeg family tragedy was Helena, George's "old feeble mother," who eventually passed on in Pittsburgh on February 6, 1941, at age 79. Fortunately the Reeg family continues to be happily represented in the 21st century by the popularity of the Piccalilli Rag, which is still performed at the occasional ragtime festival.