He worked in a railroad office in Detroit, Michigan and then moved to Chicago, Illinois when the general office moved there. Brundage became chief clerk in 1888. He studied law and received his law degree from Chicago–Kent College of Law in 1893.
Brundage served in the Illinois House of Representatives and was a Republican.
In November 1904, Brundage was elected President of the Cook County Board of Commissioners and was reelected in 1906. In 1907, Brundage served as corporation counsel for the City of Chicago.
From 1917 to 1925, Brundage served as Illinois Attorney General. Brundage committed suicide at his home in Lake Forest, Illinois, because of financial problems, by firing a bullet through his heart.