Gruppe's father, Charles Paul Gruppe, lived with his family, and worked in Holland until about 1910. Consequently, he initially studied sculpture at the Royal Academy at Antwerp. On his return to America he continued his studies at New York's Art Students League; he also worked for Herbert Adams, and then Karl Bitter. On Bitter's death in 1915, Gruppe took on the responsibility of enlarging his figure, Pomono for the Pulitzer Fountain in New York.
Following World War I, during which Gruppe served in the armed forces, he established a studio in New York and worked for Charles Cary Rumsey. Rumsey died in 1922, and again Gruppe undertook enlarging and finishing a deceased sculptor's work; this undertaking occupied him in Paris for three years. As a further tribute to Rumsey, Gruppe and the architect Cameron Clark designed the Charles Cary Rumsey International Silver Polo Cup in 1925.
Working independently, Gruppe soon became known as a modeler of garden and fountain figures, and particularly as an adept portraitist of children and young women. His Welcome, posed by the dancer Hilda Beyer, was exhibited at the Panama-Pacific Exposition in San Francisco in 1915; his The Fairy served as the finial for the Italian Towers at the same fair. Among his other public portrait works are the William Rufus King Monument in Clinton, North Carolina, and busts of Charles Lindbergh and Fritz Leiber.
In 1934, recognizing the decrepit state of many of New York's public sculptures, Gruppe brought the matter to the attention of the city's Department of Parks, and was appointed chairman of a committee of sculptors who oversaw their restoration. Shortly thereafter, he was commissioned by the city to complete a statue of Henry Hudson, based on the original designs by Karl Bitter, for the top of the shaft of the Henry Hudson Memorial which had stood unadorned since 1909. The final work was unveiled in 1938.
Gruppe exhibited frequently in New York; his work was first seen at the Academy in 1913, and remained one of the most-often represented sculptors in annuals through the 1970s. The awards conveyed on his works by the Academy were the Barnett Prize, 1926; Saltus Gold Medal, 1952; Dessie Greer Prize, 1956 (for a bust of Dwight D. Eisenhower); Watrous Medal 1969, and 1976; and the French Medal, 1974.
He was elected to the Academy Council in 1950, the same year in which he became president of the National Sculpture Society. After five years as a member of the Council he was elected Academy second vice president in 1955, and the next year, first vice president, a post to which he was reelected through 1958. In 1968 Gruppe was again elected to another three-year Council term.
