His father served as a private in the 30th Wisconsin Infantry Regiment in the Union Army during the Civil War.
In 1909–1911, Gillette served as an apprentice in the Boston office of Warren H. Manning, a leading early-20th century landscape architect.
During the 1950s, Gillette redesigned the gardens of Virginia's Executive Mansion at the request of Governor Thomas B. Stanley.
In 1958, he designed the grounds for the Reynolds Metals Company International Headquarters located at Richmond.
[2] Author Tom Wolfe references Gillette as the commissioned landscaper of Dupont University in I Am Charlotte Simmons.