He was appointed by President Theodore Roosevelt in 1902, and served until the court was abolished after statehood was granted to Oklahoma on November 16, 1907.
Born in Ashtabula County, Ohio, on January 7, 1848, Gillette had moved with his parents to Emporia, Kansas when he was thirteen.
At the end of his senatorial term, he moved to Oklahoma Territory and settled in El Reno where he opened a private law practice.
[1] On May 2, 1902, Congress created two additional positions on the Oklahoma Territory Supreme Court.
[3] He did not win, but got the second highest number of votes of any Republican candidate on the ballot.