Born in New Haven, Connecticut, Bartlett was Head of Sculpture Section at The Glasgow School of Art, 1913-1916.
His father, the sculptor and art critic Truman Howe Bartlett, took him to Paris where, aged just fifteen, he learned how to model the animals in the zoo at the Jardin des Plantes from the famous French sculptor, Emmanuel Fremiet. His extraordinary talent was soon recognized and he won a medal at the at the Paris Salon of 1887. Following this success, he was invited in 1903 to collaborate with the Dean of American Sculptors, John Quincy Adams Ward, on the models for the pediment sculptures of the New York Stock Exchange.
This led to the even more prestigious commission to create a sculpture for the pediment of the Capitol Building in Washington D.C. He designed "The Apotheosis of Democracy", his masterwork, which he began in 1908 and completed in 1916.
In Paris, where he continued to live, he designed the imposing equestrian statue of Lafayette on the Cours Albert Ler, a gift to the French Republic from American school children. Alongside all these monumental works, Bartlett continued to produce smaller bronzes of fish, insects and reptiles. Some of these works are in the Berkshire Museum collection (Mass., USA).
In 1895, he was named a Chevalier of the French Legion of Honor. In 1916 he was admitted to the American Academy of Arts and Letters. He was also a member of the National Sculpture Society and the International Society of Sculptors, Painters and Gravers
His appointment at the GSA is reported in the 1912-13 GSA Annual Report and the following year, Bartlett wrote to Newbery regarding a report on the Sculpture Section of the School.