Born in Brownsville, Pennsylvania, in May 1853, Philander Knox had an extensive career in government. A graduate of Mount Union College, Knox served as assistant U.S. attorney for the Western District of Pennsylvania between 1876 and 1877. He filled the post of attorney general in the cabinets of Presidents William McKinley and Theodore Roosevelt from 1901-1904, following which he represented Pennsylvania in the Senate from 1904 to 1909. Knox attempted unsuccessfully to earn the Republican presidential nomination in 1908.

He was the beneficiary of incoming President William Howard Taft's desire to get "the best men" for his cabinet, and thus became secretary of state upon the recommendation of outgoing secretary Elihu Root. Knox would once again fail to gain the Republican nomination for President in 1916, running successfully instead for a senate seat from Pennsylvania. Knox would die in office on October 12, 1921.