He attended Cornell University, obtaining the Bachelor of Surgery degree in 1898 and the M.S.A. degree in 1906.
He received his elementary and secondary education in Fort Worth, Texas. Upon his graduation from Cornell, he was the assistant director of the Provincial Agricultural College at Wuchang, China from 1898 to 1900, an instructor in charge of agriculture and nature study in the Honolulu Normal and Training School in 1901. He served as a fiber expert for the Philippine Bureau of Agriculture in 1902.
From 1903 to 1907, he worked as an instructor and assistant professor of Agronomy at Cornell University, followed by as a professor of Agronomy in Pennsylvania State College from 1907 and 1908.
From 1908 to 1913, he was the president of the University of Hawaii. He went on to teach as a professor of Agronomy at the University of California Davis from 1913 until his death The Gilmore Halls at University of Hawaii and at the University of California, Davis were both named in his honor.
Gilmore"s son Raymond M. Gilmore was a zoologist and expert on migration of California grey whales., and C. F., and L. J.