George Grey Barnard was born on May 24, 1863, at 113 East Linn Street, in Bellefonte, Pennsylvania. The structure, built in 1858, is still in existence. Barnard was the son of Presbyterian minister Reverend Joseph H. Barnard, of Tuscarora Valley, near Mifflintown, Pennsylvania. His mother, the former Martha Gray, was a member of the Philadelphia Gray family who operated Gray's Ferry. Barnard preferred, and thus used, the alternate spelling of his mother's maiden name. George Grey Barnard was one of four children. His siblings were Evan, May, and Barbara. The family left Bellefonte in 1866, living in Waukesha, Wisconsin; Kankakee, Illinois; and Muscatine, Iowa, respectively.

As a child, the wildlife of the prairies captured Barnard's interest, and as a result of this interest, he delved into the world of taxidermy. He was self-taught, and his specimens, over one thousand, were a subject of great local interest to his Midwestern neighbors. George Grey Barnard's first "official" employment was as an assistant to a jeweler in Muscatine. He also worked as a jeweler's engraver while living in Chicago. When Barnard was in his late teens he began his work as a sculptor. He studied briefly with a now obscure sculptor, Leonard Volk, and, under Volk's tutelage, he first worked in the medium of marble. Even when he studied in Paris as part of the Société Nationale des Beaux Arts under Pierre Jules Cavalier who thought Barnard was influenced by Rodin, Barnard insisted that this was not true. It was Michelangelo, whom he came to idolize while studying at the Art Institute of Chicago, who was the inspiration for his work. As is true for many artists, George Grey Barnard had a benefactor at the beginning of his career. Alfred Corning Clark, heir to the Singer Manufacturing Corporation, saw Barnard's potential, and was the first to commission sculpture from him. It was for Clark that Barnard's first pieces, the Boy and Brotherly Love were completed.

In 1894, while still studying in Paris, Barnard entered six of his sculptures in an exhibit sponsored by the Société Nationale des Beaux Arts at the Salon of the Champs de Mars. These six works were Barnard's first acceptance as a renowned artist. The Kankakee County Historical Society quoted a French art critic of Barnard's time who said that Barnard was "a newcomer who possesses all the qualities of a great master." One of the pieces, Struggle of the Two Natures of Man was commissioned by Alfred Clark for $25,000, and is now part of the Metropolitan Museum of Art collection. Dickson, in his 1961 article in Art Journal, used the artist's words to describe the group he labeled Victory. Barnard said, "I shall try and bring all the anguish that what we call a victor is susceptible to-that is the higher one gets the more delicate he is strung-and all the winds of life strike on him...." The marble work depicts two men, one positioned above the other, but neither showing the typical good vs. evil expression that one would expect given the title of the sculpture. It was in Paris that Barnard met Edna Monroe, a Bostonian, whom he married prior to returning to the United States. Upon their return to America, the Barnards made their home in Washington Heights, New York. The couple had three children, Monroe, Barbara, and Vivia. After returning to the States, George Grey Barnard produced a wood carving, the Norwegian Clock, as well as the sculptures The Hewer, Maidenhood, and the controversial Pan, a bronze that was rejected for placement in New York's Central Park because it was a nude. This was only one of many disappointments that Barnard faced during this time.

Barnard, being a man of strong principles and ideals, endured a period of rejection due to his refusal to conform to others' perceptions of what his work should be. Artists rely heavily upon their benefactors for their continued support, so Clark's death in 1896 was another hardship that Barnard had to face. In 1902, however, things began to improve. Barnard was commissioned to craft sculptures for the Pennsylvania State Capitol Building in Harrisburg. Because he felt that Paris was more conducive to his productivity as an artist, Barnard and his family returned there to work on these pieces in 1903. Some call this the beginning of his second French period. He remained in Paris for seven years, and during this time, enjoyed another great success at the Salon of the Champs de Mars. The sculptures that would be part of the Pennsylvania State Capitol, Burden of Life: The Broken Law and Love and Labor: The Unbroken Law, were prominently placed on either side of the entrance to the Grand Palais. This was in stark contrast to what was happening with the Harrisburg commission, which was running out of money, having been reduced from a commission of $300,000 to $100,000, and was embroiled in political scandal as well. Thanks to Barnard's friends, the project was completed, and October 4, 1911, was named "Barnard Day" by the Pennsylvania state legislature, as the works were unveiled at the main entrance to the Capitol Building in Harrisburg.

George Grey Barnard was not only a craftsman, but a collector as well. While Barnard was in Moret, France working on his commission for the Pennsylvania State Capitol, he was forced to support his family by working as a dealer in antiquities. He collected artifacts of the Middle Ages. Those relics that he retained for his private collection were later exhibited in The Cloisters. Barnard established The Cloisters as a model of a medieval monastery in 1914, in Washington Heights, New York. Barnard's collection was "the first installation of medieval art of its kind in America" according to the Metropolitan Museum of Art. According to the Dickson/Barnard Collection article from the Centre County Historical Society's container and file list, "These unique pieces of Medieval and Renaissance art from France sparked an interest in Americans, and as a result, study and collecting of this period increased significantly." The Cloisters was later purchased by J. D. Rockefeller, and is still part of the Metropolitan Museum of Art collection. The Philadelphia Museum of Art also owns artifacts of the Middle Ages that were procured by Barnard.

The other passion that George Grey Barnard had was for Abraham Lincoln. Barnard was commissioned by Mr. and Mrs. Charles P. Taft to produce a bronze of Lincoln for Lytle Park in Cincinnati, Ohio. This lifelike sculpture, copied and renowned as one of the finest likenesses of our sixteenth president, was the result of what Barnard called "my journey in the heart of Lincoln". Amazingly, this piece was the object of much controversy at its inception, with many criticizing the work as being "ugly and in poor taste." Barnard, however, felt that to change Lincoln's features in art would be a travesty. "No imitation tool of any artist's conception, but the tool God and Lincoln made - Lincoln's self - must be shown. An imaginary Lincoln is an insult to the American people, a thwarting of democracy." This single sculpture has produced three others like it, and numerous busts, one of which is displayed near Talleyrand Park in Bellefonte, and another of which is found on the campus of the Pennsylvania State University.

Barnard's final ambition was to create a magnificent, everlasting monument to peace. To this end, George Grey Barnard spent the final years of his life sculpting the plaster model, Rainbow Arch, a one hundred foot high portion of Barnard's dream of a peace monument. The final product was to be dedicated to mothers who had sacrificed their sons to war. Sadly, only the model was completed before Barnard's death, and that model was then dismantled and has since disintegrated. On April 24, 1938, just one month prior to his seventy-fifth birthday, George Grey Barnard died in New York City. His funeral was held in The Abbaye, formerly The Cloisters, that he had established in Washington Heights. Barnard is buried in the Harrisburg Cemetery in Dauphin County, Pennsylvania, pursuant to the request in his will that, "my remains on earth...rest near my Beloved group on the capital (sic) of my native state of Pennsylvania."