He was born in 1870 in St. Louis, Missouri, the son of economist and writer A. Warren Kelsey and novelist Jeanette Garr Washburn.
[1] His father had been a close friend of the artist Winslow Homer,[2] and his mother was the daughter of Wisconsin Governor Cadwallader C. Washburn.
[3] He studied town planning abroad, and returned an ardent supporter of civic improvement, carrying its doctrines, as a lecturer, through the country.
In 1899, he was elected the first president of the Architectural League of America, and devised the exhibit on municipal improvement for the 1904 St. Louis World's Fair.
The partnership was short-lived, and its only major commission was the Pan-American Union Building (now Organization of American States) in Washington, D.C.[4] Kelsey worked on his own after 1909.