Three of Saint-Gaudens' most significant relationships were with men whom he had met during his student years in Europe, and who remained in France and Italy. Although he saw these men only on his returns to Paris and Rome, their friendships remained vital. The letters exchanged between them and the sculptor provide some of the most complete details of what Saint-Gaudens thought and cared about, and give us his philosophy of art.

Paul Bion (18-1897), the son of well-known French sculptor Louis-Eugène Bion, studied sculpture with Saint-Gaudens at the École des Beaux-Arts. The two men had a lifelong friendship, sustained by copious amounts of letters from Bion to Saint-Gaudens, and renewed with each of Saint-Gaudens' trips to Paris.  Bion became less of a sculptor and more of an art critic as the years went by, offering Saint-Gaudens some very perceptive commentary on his work and on the contemporary European art scene as a whole. Saint-Gaudens grew to rely on Bion's criticism and suggestions, and on his role as intermediary in Saint-Gaudens' dealings with Parisian foundries. Tragically, Bion died shortly after penning a letter critical of the allegorical figure in the Shaw Memorial; Saint-Gaudens long struggled with this figure, and never had the chance to convince his friend of her function in the meaning of the piece.

Alfred Garnier was a student at the École des Beaux-Arts with Saint-Gaudens and Paul Bion.  He is known particularly for his work in enamels. Garnier was Saint-Gaudens' traveling companion on a walking trip to the Swiss Alps in 1869, and again in 1897, on a trip to Aspet, Bernard Saint-Gaudens' birthplace.

Dr. Henry Shiff was born in New Orleans in 1833, educated in France, and then served as a surgeon in the Confederate army. After the Civil War he practiced medicine in New York City and then went to Rome, where his appreciation for and knowledge of art brought him into artistic circles. He met Saint-Gaudens in 1870. Shiff was quite the traveler, and would frequently visit Saint-Gaudens in Paris when the sculptor moved back to that city in 1876. He was in Paris with Saint-Gaudens between 1897 and 1900,and died there about 1906. Shiff was a philosopher, and Saint-Gaudens would later say that Shiff "exerted a more powerful influence in forming what little character I have than any other man I ever met." Saint-Gaudens named his son Homer Schiff Saint-Gaudens in honor of their friendship.