In 1906, Keep along with Lawrence O. Murray (Comptroller of Currency) and Gifford Pinchot (Chief of the United States Forest Service), provided President Roosevelt with a detailed report of the organization and operations of the Department of the Interior.
The report highlighted "grave defects" in the structure of the department such as redundant job functions, an "abuse of letter writing" that impeded public business, and rampant inefficiency.
In 1907, he became the first prominent New Yorker to endorse then Secretary of War William Howard Taft for president to succeed Roosevelt.
[9] On May 17, 1894,[10] Keep was married to Margaret Turner Williams (1872–1954) at Trinity Episcopal Church in Buffalo, New York in what was described as "one of the largest weddings of the season".
[1][13] Together, they were the parents of two daughters:[9] In the mid-1920s, he bought a six-story, twenty-four-room Beaux Arts style townhouse at 9 East 89th Street in Manhattan that had been designed by Oscar Florianus Bluemner in 1901.
After his death, the 89th Street house was sold it to the American Institute for Iranian Art and Archaeology in 1942.