[1] A Republican, Philbrook served in a variety of political, legal, and judicial roles throughout the U.S. State of Maine throughout his career.

Philbrook was a Freemason and a member of the Knights of Pythias, where he served as Chancellor Commander of Maine.

Philbrook read law and was admitted to the bar of Kennebec County on October 21, 1884.

[3] In July 1905, he was appointed to be the assistant attorney general of Maine, the first holder of that office since its creation by the legislature.

[4] On April 9, 1913 he was appointed as a justice of the Maine Supreme Judicial Court by Republican governor William Haines.